/* FlashCards - Modern Dark Theme Stylesheet */
@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
    /* Colors */
    --bg-primary: #0a0a0f;
    --bg-secondary: #12121a;
    --bg-tertiary: #1a1a25;
    --bg-card: rgba(26, 26, 37, 0.7);
    --bg-glass: rgba(255, 255, 255, 0.03);

    --text-primary: #f0f0f5;
    --text-secondary: #9090a0;
    --text-muted: #606070;

    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    
    /* Primary color aliases */
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;

    --success: #22c55e;
    --success-bg: rgba(34, 197, 94, 0.15);
    --warning: #f59e0b;
    --warning-bg: rgba(245, 158, 11, 0.15);
    --danger: #ef4444;
    --danger-bg: rgba(239, 68, 68, 0.15);
    --info: #3b82f6;
    --info-bg: rgba(59, 130, 246, 0.15);

    --border-color: rgba(255, 255, 255, 0.08);
    --border-light: rgba(255, 255, 255, 0.12);

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.3);

    /* Spacing */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 28px;

    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
    --transition-slow: 0.4s ease;
}

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: 'Space Grotesk', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

/* Background Effects */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse 80% 50% at 20% -20%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 80% 100%, rgba(139, 92, 246, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    color: var(--text-primary);
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

p {
    color: var(--text-secondary);
}

a {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--accent-secondary);
}

/* Layout */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.page-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navigation */
.navbar {
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    min-height: 72px;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    min-width: 100px;
}

.navbar-brand svg {
    width: 32px;
    height: 32px;
}

.navbar-brand i {
    width: 24px;
    text-align: center;
}

.navbar-menu {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.625rem 1rem;
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    font-weight: 500;
    transition: all var(--transition-fast);
}

.nav-link i {
    width: 18px;
    text-align: center;
}

.nav-link:hover {
    background: var(--bg-glass);
    color: var(--text-primary);
}

.nav-link.active {
    background: var(--accent-gradient);
    color: white;
}

.nav-link svg {
    width: 20px;
    height: 20px;
}

/* Mobile Menu */
.menu-toggle {
    display: none;
    background: none;
    border: none;
    color: var(--text-primary);
    cursor: pointer;
    padding: 0.5rem;
}

@media (max-width: 768px) {
    .menu-toggle {
        display: block;
    }

    .navbar-menu {
        position: fixed;
        top: 65px;
        left: 0;
        right: 0;
        background: var(--bg-secondary);
        border-bottom: 1px solid var(--border-color);
        flex-direction: column;
        padding: 1rem;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-normal);
    }

    .navbar-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-link {
        width: 100%;
        justify-content: center;
    }
}

/* Cards & Containers */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    backdrop-filter: blur(10px);
    transition: all var(--transition-normal);
}

.card:hover {
    border-color: var(--border-light);
    box-shadow: var(--shadow-md);
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-family: inherit;
    font-size: 0.95rem;
    font-weight: 500;
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.btn svg {
    width: 18px;
    height: 18px;
}

.btn-primary {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 4px 15px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px rgba(99, 102, 241, 0.4);
    color: white;
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-glass);
    border-color: var(--border-light);
    color: var(--text-primary);
}

.btn-success {
    background: var(--success);
    color: white;
}

.btn-danger {
    background: var(--danger);
    color: white;
}

.btn-ghost {
    background: transparent;
    color: var(--text-secondary);
}

.btn-ghost:hover {
    background: var(--bg-glass);
    color: var(--text-primary);
}

.btn-icon {
    width: 44px;
    height: 44px;
    padding: 0;
    border-radius: var(--radius-md);
}

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.1rem;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* Forms */
.form-group {
    margin-bottom: 1.25rem;
}

.form-label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.form-control {
    width: 100%;
    padding: 0.875rem 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: all var(--transition-fast);
}

.form-control:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

.form-control::placeholder {
    color: var(--text-muted);
}

textarea.form-control {
    min-height: 120px;
    resize: vertical;
}

.form-hint {
    margin-top: 0.375rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.form-error {
    color: var(--danger);
}

/* Select */
.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='%239090a0' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    background-size: 18px;
    padding-right: 2.5rem;
}

/* Toggle Switch */
.toggle {
    position: relative;
    display: inline-block;
    width: 52px;
    height: 28px;
}

.toggle input {
    opacity: 0;
    width: 0;
    height: 0;
}

.toggle-slider {
    position: absolute;
    cursor: pointer;
    inset: 0;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: 28px;
    transition: all var(--transition-fast);
}

.toggle-slider::before {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    left: 3px;
    bottom: 3px;
    background: var(--text-secondary);
    border-radius: 50%;
    transition: all var(--transition-fast);
}

.toggle input:checked+.toggle-slider {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
}

.toggle input:checked+.toggle-slider::before {
    transform: translateX(24px);
    background: white;
}

/* Badges */
.badge {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.75rem;
    font-size: 0.8rem;
    font-weight: 500;
    border-radius: 50px;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
}

.badge-primary {
    background: rgba(99, 102, 241, 0.2);
    color: var(--accent-primary);
}

.badge-success {
    background: var(--success-bg);
    color: var(--success);
}

.badge-warning {
    background: var(--warning-bg);
    color: var(--warning);
}

.badge-danger {
    background: var(--danger-bg);
    color: var(--danger);
}

/* Alerts */
.alert {
    padding: 1rem 1.25rem;
    border-radius: var(--radius-lg);
    margin-bottom: 1rem;
    display: flex;
    align-items: flex-start;
    gap: 0.75rem;
    position: relative;
    overflow: hidden;
}

.alert::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
}

.alert i:first-child {
    font-size: 1.1rem;
    flex-shrink: 0;
    margin-top: 0.1rem;
}

.alert-content {
    flex: 1;
}

.alert-content strong {
    display: block;
    margin-bottom: 0.25rem;
}

.alert-content p {
    margin: 0.25rem 0 0 0;
    opacity: 0.85;
    font-size: 0.9rem;
}

.alert-success {
    background: linear-gradient(135deg, rgba(34, 197, 94, 0.1) 0%, rgba(34, 197, 94, 0.05) 100%);
    color: #4ade80;
    border: 1px solid rgba(34, 197, 94, 0.2);
}

.alert-success::before {
    background: linear-gradient(180deg, #22c55e, #16a34a);
}

.alert-success i:first-child {
    color: #22c55e;
}

.alert-danger {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.1) 0%, rgba(239, 68, 68, 0.05) 100%);
    color: #f87171;
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.alert-danger::before {
    background: linear-gradient(180deg, #ef4444, #dc2626);
}

.alert-danger i:first-child {
    color: #ef4444;
}

.alert-warning {
    background: linear-gradient(135deg, rgba(245, 158, 11, 0.1) 0%, rgba(245, 158, 11, 0.05) 100%);
    color: #fbbf24;
    border: 1px solid rgba(245, 158, 11, 0.2);
}

.alert-warning::before {
    background: linear-gradient(180deg, #f59e0b, #d97706);
}

.alert-warning i:first-child {
    color: #f59e0b;
}

.alert-info {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1) 0%, rgba(59, 130, 246, 0.05) 100%);
    color: #60a5fa;
    border: 1px solid rgba(59, 130, 246, 0.2);
}

.alert-info::before {
    background: linear-gradient(180deg, #3b82f6, #2563eb);
}

.alert-info i:first-child {
    color: #3b82f6;
}

/* Auth Pages */
.auth-wrapper,
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    background: var(--bg-primary);
}

.auth-card {
    width: 100%;
    max-width: 420px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 2.5rem;
    backdrop-filter: blur(20px);
    box-shadow: var(--shadow-lg);
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-logo {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.auth-logo svg {
    width: 40px;
    height: 40px;
}

.auth-subtitle {
    color: var(--text-secondary);
}

.auth-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    background: var(--bg-tertiary);
    padding: 0.25rem;
    border-radius: var(--radius-md);
}

.auth-tab {
    flex: 1;
    padding: 0.75rem;
    text-align: center;
    border-radius: var(--radius-sm);
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    background: none;
}

.auth-tab.active {
    background: var(--accent-gradient);
    color: white;
}

.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.auth-footer {
    text-align: center;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* Dashboard */
.dashboard-header {
    padding: 2rem 0;
    margin-bottom: 2rem;
}

.welcome-text {
    color: var(--text-secondary);
    margin-bottom: 0.25rem;
}

.dashboard-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

/* Stats Cards */
.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    transition: all var(--transition-normal);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

.stat-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-md);
    flex-shrink: 0;
}

.stat-icon svg {
    width: 24px;
    height: 24px;
}

.stat-icon.purple {
    background: rgba(99, 102, 241, 0.2);
    color: var(--accent-primary);
}

.stat-icon.green {
    background: var(--success-bg);
    color: var(--success);
}

.stat-icon.orange {
    background: var(--warning-bg);
    color: var(--warning);
}

.stat-icon.blue {
    background: var(--info-bg);
    color: var(--info);
}

.stat-content h3 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.stat-content p {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Category Cards */
.category-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.category-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.category-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--category-color, var(--accent-gradient));
}

.category-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--border-light);
}

.category-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.category-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.category-meta {
    display: flex;
    gap: 0.75rem;
    font-size: 0.875rem;
    color: var(--text-muted);
}

.category-meta.category-author {
    margin-top: 0.35rem;
}

.category-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.category-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.category-stats {
    display: flex;
    gap: 1rem;
}

.category-stat {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.category-stat svg {
    width: 16px;
    height: 16px;
}

.category-progress-wrapper {
    flex: 1;
    margin-right: 1rem;
}

.category-progress-bar {
    height: 6px;
    background: var(--bg-tertiary);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 0.25rem;
}

.category-progress-fill {
    height: 100%;
    background: var(--accent-gradient);
    border-radius: 3px;
    transition: width 0.3s ease;
}

.category-progress-text {
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    background: var(--bg-card);
    border: 1px dashed var(--border-color);
    border-radius: var(--radius-lg);
}

.empty-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.5rem;
    background: var(--bg-tertiary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
}

.empty-icon svg {
    width: 40px;
    height: 40px;
}

.empty-state h3 {
    margin-bottom: 0.5rem;
}

.empty-state p {
    margin-bottom: 1.5rem;
}

/* Study Mode - Flashcard */
.study-container {
    max-width: 600px;
    margin: 0 auto;
    padding: 1rem;
}

.study-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    gap: 1rem;
}

.study-progress {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex-shrink: 0;
}

.progress-bar {
    width: 120px;
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: 4px;
    overflow: hidden;
}

@media (min-width: 480px) {
    .progress-bar {
        width: 180px;
    }
}

.progress-fill {
    height: 100%;
    background: var(--accent-gradient);
    transition: width var(--transition-normal);
}

.progress-text {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Flashcard Stack */
.flashcard-stack {
    position: relative;
    height: 400px;
    perspective: 1000px;
    margin-bottom: 2rem;
    touch-action: pan-y;
}

.flashcard {
    position: absolute;
    width: 100%;
    height: 100%;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 2rem;
    display: flex;
    flex-direction: column;
    cursor: grab;
    user-select: none;
    transition: transform 0.1s ease, box-shadow var(--transition-normal);
    transform-style: preserve-3d;
    backface-visibility: hidden;
}

.flashcard:active {
    cursor: grabbing;
}

.flashcard.dragging {
    transition: none;
    z-index: 10;
}

.flashcard.swiping-right {
    background: linear-gradient(135deg, var(--bg-card) 0%, var(--success-bg) 100%);
    border-color: var(--success);
}

.flashcard.swiping-left {
    background: linear-gradient(135deg, var(--bg-card) 0%, var(--danger-bg) 100%);
    border-color: var(--danger);
}

.flashcard.swiping-up {
    background: linear-gradient(135deg, var(--bg-card) 0%, var(--warning-bg) 100%);
    border-color: var(--warning);
}

.flashcard-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

.flashcard-question {
    font-size: 1.5rem;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 1rem;
}

.flashcard-answer {
    font-size: 1.25rem;
    color: var(--text-secondary);
    display: none;
    animation: revealAnswer 0.4s ease;
}

.flashcard.revealed .flashcard-answer {
    display: block;
}

@keyframes revealAnswer {
    from {
        opacity: 0;
        transform: translateY(20px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.flashcard-hint {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    font-size: 0.9rem;
    color: var(--text-muted);
}

.flashcard-footer {
    display: flex;
    justify-content: center;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.reveal-btn {
    padding: 0.75rem 2rem;
}

/* Swipe Indicators */
.swipe-indicators {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    padding: 0 0.5rem;
}

.swipe-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    opacity: 0.6;
    transition: opacity var(--transition-fast);
}

.swipe-indicator.active {
    opacity: 1;
}

.swipe-indicator-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-size: 1.5rem;
}

.swipe-indicator.wrong .swipe-indicator-icon {
    background: var(--danger-bg);
    color: var(--danger);
}

.swipe-indicator.skip .swipe-indicator-icon {
    background: var(--warning-bg);
    color: var(--warning);
}

.swipe-indicator.correct .swipe-indicator-icon {
    background: var(--success-bg);
    color: var(--success);
}

.swipe-indicator span {
    font-size: 0.8rem;
    color: var(--text-muted);
}

/* Action Buttons (Desktop) */
.study-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
}

.action-btn {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    border: none;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.action-btn:hover {
    transform: scale(1.1);
}

.action-btn.wrong {
    background: var(--danger-bg);
    color: var(--danger);
    border: 2px solid var(--danger);
}

.action-btn.skip {
    background: var(--warning-bg);
    color: var(--warning);
    border: 2px solid var(--warning);
}

.action-btn.correct {
    background: var(--success-bg);
    color: var(--success);
    border: 2px solid var(--success);
}

/* Swipe Animation Overlays */
.swipe-overlay {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    font-size: 3rem;
    font-weight: 700;
    opacity: 0;
    transition: opacity var(--transition-fast);
    pointer-events: none;
    z-index: 20;
}

.swipe-overlay.left {
    left: 2rem;
    color: var(--danger);
}

.swipe-overlay.right {
    right: 2rem;
    color: var(--success);
}

.swipe-overlay.up {
    left: 50%;
    transform: translate(-50%, -50%);
    color: var(--warning);
}

.flashcard.swiping-left .swipe-overlay.left,
.flashcard.swiping-right .swipe-overlay.right,
.flashcard.swiping-up .swipe-overlay.up {
    opacity: 1;
}

/* Fly Away Animations */
@keyframes flyRight {
    to {
        transform: translateX(120vw) rotate(30deg);
        opacity: 0;
    }
}

@keyframes flyLeft {
    to {
        transform: translateX(-120vw) rotate(-30deg);
        opacity: 0;
    }
}

@keyframes flyUp {
    to {
        transform: translateY(-100vh);
        opacity: 0;
    }
}

.flashcard.fly-right {
    animation: flyRight 0.4s ease forwards;
}

.flashcard.fly-left {
    animation: flyLeft 0.4s ease forwards;
}

.flashcard.fly-up {
    animation: flyUp 0.4s ease forwards;
}

/* Study Complete */
.study-complete {
    text-align: center;
    padding: 3rem 2rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
}

.study-complete-icon {
    width: 100px;
    height: 100px;
    margin: 0 auto 1.5rem;
    background: var(--success-bg);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 3rem;
    animation: celebrateIcon 0.6s ease;
}

@keyframes celebrateIcon {
    0%, 100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.2);
    }
}

.study-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin: 2rem 0;
}

.study-stat {
    text-align: center;
}

.study-stat-value {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.study-stat-value.correct {
    color: var(--success);
}

.study-stat-value.wrong {
    color: var(--danger);
}

.study-stat-value.skipped {
    color: var(--warning);
}

.study-stat-label {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* Browse Page */
.browse-header {
    padding: 2rem 0;
}

.search-box {
    display: flex;
    gap: 0.75rem;
    margin-top: 1.5rem;
}

.search-input {
    flex: 1;
    min-width: 0;
    padding: 0.875rem 1.25rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 1rem;
}

.search-input:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.browse-filters {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
    flex-wrap: wrap;
}

.browse-filters .btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
}

/* Mobile: Hide button text, show only icons */
@media (max-width: 640px) {
    .browse-header {
        padding: 1rem 0;
    }

    .search-box {
        gap: 0.5rem;
        margin-top: 1rem;
    }

    .search-input {
        padding: 0.75rem 1rem;
        font-size: 0.9rem;
    }

    .search-box .btn .btn-text {
        display: none;
    }

    .search-box .btn {
        padding: 0.75rem 1rem;
    }

    .browse-filters .btn-text {
        display: none;
    }

    .browse-filters .btn {
        padding: 0.5rem 0.75rem;
    }

    .browse-filters .btn i {
        margin: 0;
    }
}

/* Profile Page */
.profile-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 1.5rem;
    padding: 2rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    margin-bottom: 2rem;
}

.profile-info {
    display: flex;
    flex-direction: row;
    align-items: center;
    gap: 1.5rem;
}

.profile-avatar-wrapper {
    position: relative;
    display: inline-block;
    flex-shrink: 0;
}

.profile-avatar {
    width: 100px;
    height: 100px;
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
}

.profile-details {
    display: flex;
    flex-direction: column;
}

.profile-details h1 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 0 0.25rem 0;
    flex-wrap: wrap;
}

.profile-details>.text-muted {
    margin: 0 0 0.5rem 0;
}

.profile-public-link {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    font-size: 0.85rem;
    color: var(--accent-primary);
    text-decoration: none;
    transition: var(--transition-fast);
}

.profile-public-link:hover {
    color: var(--accent-secondary);
}

.profile-username-line {
    color: var(--text-muted);
    margin: 0 0 0.75rem 0;
}

.profile-public-link-card {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    text-decoration: none;
    transition: var(--transition-fast);
    font-size: 0.85rem;
}

.profile-public-link-card:hover {
    background: var(--bg-secondary);
    border-color: var(--accent-primary);
}

.profile-public-url {
    color: var(--text-secondary);
    font-family: 'Monaco', 'Consolas', monospace;
    font-size: 0.8rem;
}

.profile-public-link-card i {
    color: var(--accent-primary);
    font-size: 0.75rem;
}

.profile-edit-btn {
    flex-shrink: 0;
    align-self: flex-start;
}

@media (max-width: 640px) {
    .profile-header {
        flex-direction: column;
        align-items: stretch;
    }

    .profile-info {
        flex-direction: column;
        text-align: center;
    }

    .profile-details h1 {
        justify-content: center;
    }

    .profile-public-link {
        justify-content: center;
    }

    .profile-header>.btn {
        align-self: center;
    }
}

.level-badge-avatar {
    position: absolute;
    bottom: -8px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem 0.6rem;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 700;
    white-space: nowrap;
    border: 2px solid var(--bg-card);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3);
}

.level-badge-avatar i {
    font-size: 0.65rem;
}

/* Level Tiers */
.tier-bronze {
    background: linear-gradient(135deg, #cd7f32, #a0522d);
    color: white;
}

.tier-silver {
    background: linear-gradient(135deg, #c0c0c0, #808080);
    color: #1a1a2e;
}

.tier-gold {
    background: linear-gradient(135deg, #ffd700, #daa520);
    color: #1a1a2e;
    box-shadow: 0 2px 12px rgba(255, 215, 0, 0.4);
}

.tier-diamond {
    background: linear-gradient(135deg, #b9f2ff, #00d4ff, #7b68ee);
    color: #1a1a2e;
    box-shadow: 0 2px 16px rgba(0, 212, 255, 0.5);
    animation: diamondShine 2s ease-in-out infinite;
}

@keyframes diamondShine {
    0%, 100% {
        box-shadow: 0 2px 16px rgba(0, 212, 255, 0.5);
    }

    50% {
        box-shadow: 0 2px 24px rgba(185, 242, 255, 0.8);
    }
}

.profile-info h1 {
    margin-bottom: 0.25rem;
}

.profile-info p {
    color: var(--text-muted);
}

.profile-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

/* Admin Panel */
.admin-tabs {
    display: flex;
    gap: 0.25rem;
    margin-bottom: 2rem;
    padding: 0.25rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
}

.admin-tabs::-webkit-scrollbar {
    height: 4px;
}

.admin-tabs::-webkit-scrollbar-track {
    background: transparent;
}

.admin-tabs::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

.admin-tab {
    padding: 0.6rem 1rem;
    border-radius: var(--radius-sm);
    font-weight: 500;
    font-size: 0.875rem;
    color: var(--text-secondary);
    cursor: pointer;
    border: none;
    background: none;
    transition: all var(--transition-fast);
    white-space: nowrap;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-shrink: 0;
}

.admin-tab:hover {
    color: var(--text-primary);
    background: rgba(255, 255, 255, 0.05);
}

.admin-tab.active {
    background: var(--accent-gradient);
    color: white;
}

.admin-tab span {
    display: inline;
}

@media (max-width: 768px) {
    .admin-tabs {
        margin-bottom: 1.5rem;
    }

    .admin-tab {
        padding: 0.5rem 0.75rem;
        font-size: 0.8rem;
    }

    .admin-tab span {
        display: none;
    }

    .admin-tab i {
        font-size: 1rem;
    }
}

/* Table */
.table-wrapper,
.table-responsive {
    overflow-x: auto;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    width: 100%;
}

.table,
.admin-table {
    width: 100%;
    border-collapse: collapse;
}

.table th,
.table td,
.admin-table th,
.admin-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.table th,
.admin-table th {
    background: var(--bg-tertiary);
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.85rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.table tr:last-child td,
.admin-table tr:last-child td {
    border-bottom: none;
}

.table tr:hover td,
.admin-table tr:hover td {
    background: var(--bg-glass);
}

/* Modal */
.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-fast);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    width: 100%;
    max-width: 500px;
    max-height: 90vh;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    overflow: hidden;
    transform: scale(0.9);
    transition: transform var(--transition-fast);
}

.modal-overlay.active .modal {
    transform: scale(1);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.modal-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.modal-close {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    background: none;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
}

.modal-close:hover {
    background: var(--bg-glass);
    color: var(--text-primary);
}

.modal-body {
    padding: 1.5rem;
    overflow-y: auto;
}

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    padding: 1.5rem;
    border-top: 1px solid var(--border-color);
}

/* Utilities */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.text-muted {
    color: var(--text-muted);
}

.text-success {
    color: var(--success);
}

.text-danger {
    color: var(--danger);
}

.text-warning {
    color: var(--warning);
}

.text-primary {
    color: var(--accent-primary);
}

.text-info {
    color: var(--info);
}

.author-link {
    color: inherit;
    text-decoration: none;
    transition: color var(--transition-fast);
}

.author-link:hover {
    color: var(--accent-primary);
}

.author-with-badges {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
}

.flex {
    display: flex;
}

.inline-form {
    display: contents;
}

.flex-col {
    flex-direction: column;
}

.items-center {
    align-items: center;
}

.justify-between {
    justify-content: space-between;
}

.justify-center {
    justify-content: center;
}

.gap-1 {
    gap: 0.5rem;
}

.gap-2 {
    gap: 1rem;
}

.gap-3 {
    gap: 1.5rem;
}

.mt-1 {
    margin-top: 0.5rem;
}

.mt-2 {
    margin-top: 1rem;
}

.mt-3 {
    margin-top: 1.5rem;
}

.mb-1 {
    margin-bottom: 0.5rem;
}

.mb-2 {
    margin-bottom: 1rem;
}

.mb-3 {
    margin-bottom: 1.5rem;
}

.hidden {
    display: none !important;
}

.visible {
    display: block !important;
}

/* Responsive */
@media (max-width: 640px) {
    h1 {
        font-size: 1.75rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    h3 {
        font-size: 1.25rem;
    }

    .auth-card {
        padding: 1.5rem;
    }

    .dashboard-grid {
        grid-template-columns: 1fr;
    }

    .category-grid {
        grid-template-columns: 1fr;
    }

    .flashcard-stack {
        height: 350px;
    }

    .flashcard-question {
        font-size: 1.25rem;
    }

    .profile-header {
        flex-direction: column;
        text-align: center;
    }

    .study-stats {
        gap: 1rem;
    }

    .study-stat-value {
        font-size: 1.5rem;
    }
}

/* ================================
   NEW: Profile Page Styles
   ================================ */

.profile-page {
    max-width: 900px;
    margin: 0 auto;
}

.profile-header-card {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    padding: 2rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    margin-bottom: 2rem;
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-md);
}

.profile-header-content {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.profile-avatar-large {
    width: 90px;
    height: 90px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.25rem;
    font-weight: 700;
    color: white;
    flex-shrink: 0;
    box-shadow: 0 0 30px rgba(99, 102, 241, 0.3);
}

/* Public profile page (user.php) specific styles */
.public-profile .profile-info {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.public-profile .profile-info h1 {
    margin: 0;
    font-size: 1.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.profile-username {
    color: var(--accent-primary);
    font-weight: 500;
    font-size: 1.1rem;
    margin: 0;
}

.profile-meta {
    color: var(--text-muted);
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.25rem;
}

.profile-badges {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-top: 0.5rem;
}

/* Verified Badge */
.verified-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    border-radius: 4px;
    background: rgba(29, 155, 240, 0.15);
    color: #1d9bf0;
    font-size: 0.6rem;
    border: 1px solid rgba(29, 155, 240, 0.3);
}

.verified-badge.badge-sm {
    width: 14px;
    height: 14px;
    font-size: 0.45rem;
}

.verified-badge-full {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.3rem 0.75rem;
    background: rgba(29, 155, 240, 0.15);
    color: #1d9bf0;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.verified-badge-full i {
    font-size: 0.75rem;
}

/* Admin Badge */
.admin-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    border-radius: 4px;
    background: var(--danger-bg);
    color: var(--danger);
    font-size: 0.6rem;
    border: 1px solid rgba(220, 38, 38, 0.3);
}

.admin-badge.badge-sm {
    width: 14px;
    height: 14px;
    font-size: 0.45rem;
}

.admin-badge-full {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.3rem 0.75rem;
    background: var(--danger-bg);
    color: var(--danger);
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.admin-badge-full i {
    font-size: 0.75rem;
}

/* Profile Stats Section */
.profile-stats-section {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.stats-section {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
}

.stats-section .section-title {
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border-color);
}

.section-title {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.1rem;
    margin: 0;
    color: var(--text-primary);
}

.section-title i {
    color: var(--accent-primary);
}

.stats-grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.stats-grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
}

.stats-grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.stat-card-compact {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.stat-card-compact .stat-icon {
    width: 45px;
    height: 45px;
    flex-shrink: 0;
}

.stat-card-compact .stat-content h3 {
    font-size: 1.35rem;
    margin: 0;
}

.stat-card-compact .stat-content p {
    font-size: 0.8rem;
    margin: 0;
    color: var(--text-muted);
}

.stat-card-large {
    text-align: center;
    padding: 1.5rem;
}

.stat-card-large .stat-icon {
    width: 60px;
    height: 60px;
    margin: 0 auto 0.75rem;
}

.stat-card-large .stat-icon i {
    font-size: 1.5rem;
}

.stat-card-large .stat-content h3 {
    font-size: 2rem;
    margin-bottom: 0.25rem;
}

.stat-card-large .stat-content h3 small {
    font-size: 1rem;
    font-weight: 400;
    color: var(--text-muted);
}

.stat-card-large .stat-content p {
    font-size: 0.85rem;
}

.profile-edit-section {
    max-width: 600px;
}

/* Public Profile */
.public-profile-page {
    max-width: 800px;
    margin: 0 auto;
}

.public-profile-header {
    text-align: center;
    padding: 3rem 2rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    margin-bottom: 2rem;
    position: relative;
    overflow: hidden;
}

.public-profile-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 100px;
    background: var(--accent-gradient);
    opacity: 0.1;
}

.public-profile-avatar {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
    position: relative;
    box-shadow: 0 0 40px rgba(99, 102, 241, 0.4);
}

.public-profile-header h1 {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
}

.public-profile-header .profile-username {
    font-size: 1.25rem;
}

.public-profile-stats {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 1.5rem;
    padding-top: 1.5rem;
    border-top: 1px solid var(--border-color);
}

.public-stat {
    text-align: center;
}

.public-stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.public-stat-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

@media (max-width: 768px) {
    .profile-header-card {
        flex-direction: column;
        text-align: center;
        padding: 1.5rem;
    }

    .profile-header-content {
        flex-direction: column;
    }

    .profile-info h1 {
        justify-content: center;
    }

    .profile-badges {
        justify-content: center;
    }

    .stats-grid-3 {
        grid-template-columns: 1fr;
    }

    .stats-grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }

    .public-profile-stats {
        flex-wrap: wrap;
        gap: 1.5rem;
    }
}

@media (max-width: 480px) {
    .stats-grid-4 {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .profile-header-card {
        flex-direction: column;
        text-align: center;
    }

    .profile-header-content {
        flex-direction: column;
    }

    .stats-grid-3,
    .stats-grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 480px) {

    .stats-grid-3,
    .stats-grid-4 {
        grid-template-columns: 1fr;
    }
}

/* ================================
   NEW: Tags Styles
   ================================ */

.category-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 0.5rem;
    padding-top: 0.5rem;
    padding-bottom: 0.5rem;
    border-top: 1px solid var(--border-color);
}

.tag {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.75rem;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(139, 92, 246, 0.15) 100%);
    color: var(--accent-primary);
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition-fast);
    border: 1px solid rgba(99, 102, 241, 0.2);
}

.tag::before {
    content: '#';
    opacity: 0.6;
}

.tag:hover {
    background: var(--accent-primary);
    color: white;
    border-color: var(--accent-primary);
    transform: translateY(-1px);
}

.tag:hover::before {
    opacity: 1;
}

.tag-more {
    background: transparent;
    border: 1px dashed var(--border-light);
    color: var(--text-muted);
}

.tag-more::before {
    content: '';
}

/* Tag Input System */
.tag-input-container {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    min-height: 50px;
    cursor: text;
    transition: var(--transition-fast);
}

.tag-input-container:focus-within {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.tag-input-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    align-items: center;
}

.tag-input-field {
    flex: 1;
    min-width: 150px;
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-primary);
    font-size: 0.95rem;
    padding: 0.25rem;
}

.tag-input-field::placeholder {
    color: var(--text-muted);
}

.tag-chip {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.4rem 0.5rem 0.4rem 0.85rem;
    background: linear-gradient(135deg, var(--accent-primary) 0%, var(--accent-secondary) 100%);
    color: white;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
    animation: tagPopIn 0.2s ease;
}

@keyframes tagPopIn {
    0% {
        transform: scale(0.8);
        opacity: 0;
    }

    100% {
        transform: scale(1);
        opacity: 1;
    }
}

.tag-chip-remove {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition-fast);
    line-height: 1;
}

.tag-chip-remove:hover {
    background: rgba(255, 255, 255, 0.4);
    transform: scale(1.1);
}

.popular-tags-section {
    margin-bottom: 2rem;
    padding: 1.5rem;
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.section-title-small {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.section-title-small i {
    color: var(--warning);
}

.tags-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag-link {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border-radius: 20px;
    font-size: 0.875rem;
    text-decoration: none;
    transition: var(--transition-fast);
    border: 1px solid var(--border-color);
}

.tag-link:hover,
.tag-link.active {
    background: var(--accent-primary);
    color: white;
    border-color: var(--accent-primary);
}

.tag-count {
    background: rgba(255, 255, 255, 0.2);
    padding: 0.1rem 0.4rem;
    border-radius: 10px;
    font-size: 0.75rem;
}

.search-info {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
    padding: 1rem;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.search-info p {
    margin: 0;
    color: var(--text-secondary);
}

.search-info em {
    color: var(--accent-primary);
}

/* ================================
   NEW: Confetti Animation
   ================================ */

.confetti-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    overflow: hidden;
    z-index: 1000;
}

.confetti {
    position: absolute;
    width: 10px;
    height: 10px;
    opacity: 0;
    animation: confetti-fall 3s ease-out forwards;
}

.confetti.circle {
    border-radius: 50%;
}

.confetti.square {
    border-radius: 2px;
}

.confetti.triangle {
    width: 0;
    height: 0;
    border-left: 5px solid transparent;
    border-right: 5px solid transparent;
    border-bottom: 10px solid currentColor;
    background: transparent !important;
}

@keyframes confetti-fall {
    0% {
        opacity: 1;
        transform: translateY(-100px) rotate(0deg) scale(1);
    }

    100% {
        opacity: 0;
        transform: translateY(100vh) rotate(720deg) scale(0.5);
    }
}

/* ================================
   NEW: Swipe Background Animation
   ================================ */

.study-container {
    position: relative;
    min-height: 80vh;
}

/* Prevent body scroll during swipe */
body.swiping {
    overflow: hidden;
}

.swipe-bg-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: -1;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.swipe-bg-animation.active {
    opacity: 1;
}

.swipe-bg-animation.correct {
    background: radial-gradient(ellipse at center, rgba(34, 197, 94, 0.15) 0%, transparent 70%);
}

.swipe-bg-animation.wrong {
    background: radial-gradient(ellipse at center, rgba(239, 68, 68, 0.15) 0%, transparent 70%);
}

.swipe-bg-animation.skip {
    background: radial-gradient(ellipse at center, rgba(245, 158, 11, 0.15) 0%, transparent 70%);
}

/* Pulse effect on card */
.flashcard.swiping-right {
    box-shadow: 0 0 60px rgba(34, 197, 94, 0.4);
}

.flashcard.swiping-left {
    box-shadow: 0 0 60px rgba(239, 68, 68, 0.4);
}

.flashcard.swiping-up {
    box-shadow: 0 0 60px rgba(245, 158, 11, 0.4);
}

/* Study complete celebration */
.study-complete {
    text-align: center;
    padding: 3rem 2rem;
    animation: fadeIn 0.5s ease;
}

.study-complete-icon {
    font-size: 5rem;
    margin-bottom: 1.5rem;
    animation: celebrateIcon 0.6s ease;
}

.study-complete-icon i {
    color: #f59e0b;
    filter: drop-shadow(0 0 20px rgba(245, 158, 11, 0.5));
}

@keyframes celebrateIcon {
    0% {
        transform: scale(0) rotate(-180deg);
        opacity: 0;
    }

    50% {
        transform: scale(1.2) rotate(10deg);
    }

    100% {
        transform: scale(1) rotate(0deg);
        opacity: 1;
    }
}

/* ================================
   Featured Categories
   ================================ */

.featured-section {
    margin-bottom: 2rem;
}

.featured-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.featured-header h2 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0;
}

.featured-badge,
.featured-badge-large {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.featured-badge {
    color: #f59e0b;
    font-size: 1rem;
}

.featured-badge-large {
    font-size: 1.5rem;
    color: #f59e0b;
}

.featured-badge i,
.featured-badge-large i {
    animation: flameWiggle 0.8s ease-in-out infinite;
    filter: drop-shadow(0 0 6px rgba(245, 158, 11, 0.8));
}

@keyframes flameWiggle {
    0%, 100% {
        transform: rotate(-3deg) scale(1);
        filter: drop-shadow(0 0 6px rgba(245, 158, 11, 0.8));
    }

    25% {
        transform: rotate(3deg) scale(1.05);
        filter: drop-shadow(0 0 10px rgba(239, 68, 68, 0.9));
    }

    50% {
        transform: rotate(-2deg) scale(1.1);
        filter: drop-shadow(0 0 12px rgba(245, 158, 11, 1));
    }

    75% {
        transform: rotate(2deg) scale(1.05);
        filter: drop-shadow(0 0 8px rgba(239, 68, 68, 0.8));
    }
}

/* Featured Category Card - simplified, focus on fire */
.category-card-featured {
    position: relative;
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-top: 3px solid #f59e0b;
    overflow: visible;
}

/* Override the default ::before bar for featured cards */
.category-card-featured::before {
    display: none;
}

/* Fire Animation */
@keyframes scaleUpDown {
    0%, 100% {
        transform: scaleY(1) scaleX(1);
    }

    50%, 90% {
        transform: scaleY(1.1);
    }

    75% {
        transform: scaleY(0.95);
    }

    80% {
        transform: scaleX(0.95);
    }
}

@keyframes fireShake {
    0%, 100% {
        transform: skewX(0) scale(1);
    }

    50% {
        transform: skewX(5deg) scale(0.9);
    }
}

@keyframes particleUp {
    0% {
        opacity: 0;
    }

    20% {
        opacity: 1;
    }

    80% {
        opacity: 1;
    }

    100% {
        opacity: 0;
        top: -100%;
        transform: scale(0.5);
    }
}

@keyframes fireGlow {
    0%, 100% {
        background-color: #ef5a00;
    }

    50% {
        background-color: #ff7800;
    }
}

.featured-fire {
    position: absolute;
    top: -8px;
    right: -8px;
    width: 36px;
    height: 36px;
    background-color: transparent;
    z-index: 3;
    pointer-events: none;
    filter: drop-shadow(0 2px 4px rgba(255, 100, 0, 0.5));
}

.featured-fire .fire-center {
    position: absolute;
    height: 100%;
    width: 100%;
    animation: scaleUpDown 3s ease-out infinite both;
}

.featured-fire .fire-center .main-fire {
    position: absolute;
    width: 100%;
    height: 100%;
    background-image: radial-gradient(farthest-corner at 10px 0, #d43300 0%, #ef5a00 95%);
    transform: scaleX(0.8) rotate(45deg);
    border-radius: 0 40% 60% 40%;
}

.featured-fire .fire-center .particle-fire {
    position: absolute;
    top: 60%;
    left: 45%;
    width: 8px;
    height: 8px;
    background-color: #ef5a00;
    border-radius: 50%;
    animation: particleUp 2s ease-out infinite both;
}

.featured-fire .fire-right {
    height: 100%;
    width: 100%;
    position: absolute;
    animation: fireShake 2s ease-out infinite both;
}

.featured-fire .fire-right .main-fire {
    position: absolute;
    top: 15%;
    right: -20%;
    width: 70%;
    height: 70%;
    background-color: #ef5a00;
    transform: scaleX(0.8) rotate(45deg);
    border-radius: 0 40% 60% 40%;
}

.featured-fire .fire-right .particle-fire {
    position: absolute;
    top: 45%;
    left: 50%;
    width: 10px;
    height: 10px;
    background-color: #ef5a00;
    transform: scaleX(0.8) rotate(45deg);
    border-radius: 50%;
    animation: particleUp 2s ease-out infinite both;
}

.featured-fire .fire-left {
    position: absolute;
    height: 100%;
    width: 100%;
    animation: fireShake 3s ease-out infinite both;
}

.featured-fire .fire-left .main-fire {
    position: absolute;
    top: 15%;
    left: -15%;
    width: 70%;
    height: 70%;
    background-color: #ef5a00;
    transform: scaleX(0.8) rotate(45deg);
    border-radius: 0 40% 60% 40%;
}

.featured-fire .fire-left .particle-fire {
    position: absolute;
    top: 10%;
    left: 20%;
    width: 8%;
    height: 8%;
    background-color: #ef5a00;
    border-radius: 50%;
    filter: drop-shadow(0 0 10px #d43322);
    animation: particleUp 3s ease-out infinite both;
}

.featured-fire .fire-bottom .main-fire {
    position: absolute;
    top: 30%;
    left: 20%;
    width: 70%;
    height: 70%;
    background-color: #ff7800;
    transform: scaleX(0.8) rotate(45deg);
    border-radius: 0 40% 100% 40%;
    filter: blur(8px);
    animation: fireGlow 2s ease-out infinite both;
}

/* ================================
   Charts & Statistics
   ================================ */

.chart-container {
    position: relative;
    height: 200px;
    margin: 1rem 0;
}

.chart-container.chart-lg {
    height: 280px;
}

.mini-chart {
    height: 60px;
    margin-top: 0.5rem;
}

.stats-chart-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

.chart-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
}

.chart-card-title {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.chart-card-title i {
    color: var(--accent-primary);
}

/* ================================
   Gamification & Achievements
   ================================ */

.xp-bar-container {
    background: var(--bg-tertiary);
    border-radius: 20px;
    padding: 0.25rem;
    margin: 1rem 0;
}

.xp-bar {
    height: 12px;
    background: var(--accent-gradient);
    border-radius: 20px;
    transition: width 0.5s ease;
    position: relative;
    overflow: hidden;
}

.xp-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: xpShine 2s ease-in-out infinite;
}

@keyframes xpShine {
    0% {
        transform: translateX(-100%);
    }

    100% {
        transform: translateX(100%);
    }
}

.xp-info {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
}

.level-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.75rem;
    background: linear-gradient(135deg, #cd7f32, #a0522d);
    /* Default: Bronze */
    color: white;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.level-badge.tier-bronze {
    background: linear-gradient(135deg, #cd7f32, #a0522d);
    color: white;
}

.level-badge.tier-silver {
    background: linear-gradient(135deg, #c0c0c0, #808080);
    color: #1a1a2e;
}

.level-badge.tier-gold {
    background: linear-gradient(135deg, #ffd700, #daa520);
    color: #1a1a2e;
    box-shadow: 0 2px 12px rgba(255, 215, 0, 0.4);
}

.level-badge.tier-diamond {
    background: linear-gradient(135deg, #b9f2ff, #00d4ff, #7b68ee);
    color: #1a1a2e;
    box-shadow: 0 2px 16px rgba(0, 212, 255, 0.5);
    animation: diamondShine 2s ease-in-out infinite;
}

.level-badge i {
    font-size: 0.75rem;
}

.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.achievement-card {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 1rem;
    text-align: center;
    transition: var(--transition-fast);
    position: relative;
    overflow: hidden;
}

.achievement-card.locked {
    opacity: 0.5;
    filter: grayscale(1);
}

.achievement-card.unlocked {
    border-color: var(--accent-primary);
    background: linear-gradient(145deg, var(--bg-tertiary), rgba(99, 102, 241, 0.1));
}

.achievement-card.unlocked::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent-gradient);
}

.achievement-icon {
    font-size: 1.75rem;
    margin: 0 auto 0.5rem auto;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--bg-tertiary);
    color: var(--text-muted);
}

.achievement-card.unlocked .achievement-icon {
    background: linear-gradient(135deg, var(--accent-primary), #8b5cf6);
    color: white;
    animation: achievementPop 0.5s ease;
}

.achievement-card.locked .achievement-icon {
    opacity: 0.5;
}

@keyframes achievementPop {
    0% {
        transform: scale(0);
    }

    50% {
        transform: scale(1.2);
    }

    100% {
        transform: scale(1);
    }
}

.achievement-name {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.achievement-desc {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.achievement-xp {
    color: var(--success);
    font-size: 0.75rem;
    font-weight: 600;
    margin-top: 0.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.25rem;
}

.achievement-xp i {
    font-size: 0.65rem;
}

/* Collapsible Achievements */
.card-header-collapsible {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.collapse-toggle {
    transition: transform var(--transition-fast);
}

.collapse-toggle.collapsed i {
    transform: rotate(-90deg);
}

.collapsible {
    max-height: 2000px;
    overflow: hidden;
    transition: max-height 0.4s ease-in-out, opacity 0.3s ease;
    opacity: 1;
}

.collapsible.collapsed {
    max-height: 0;
    opacity: 0;
    margin-top: 0 !important;
}

.streak-display {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    background: linear-gradient(135deg, rgba(245, 158, 11, 0.15), rgba(239, 68, 68, 0.1));
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-radius: var(--radius-md);
}

.streak-icon {
    font-size: 1.5rem;
    color: #f59e0b;
}

.streak-count {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.streak-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.daily-goal-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
    margin-bottom: 1.5rem;
}

.daily-goal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.daily-goal-title {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 600;
}

.daily-goal-title i {
    color: var(--warning);
}

/* Daily goal progress bar - same color as icon */
.daily-goal-bar {
    background: linear-gradient(90deg, var(--warning), #ea580c) !important;
}

.goal-progress-ring {
    width: 80px;
    height: 80px;
    margin: 0 auto;
}

.goal-progress-ring circle {
    fill: none;
    stroke-width: 8;
}

.goal-progress-ring .bg {
    stroke: var(--bg-tertiary);
}

.goal-progress-ring .progress {
    stroke: var(--success);
    stroke-linecap: round;
    transform: rotate(-90deg);
    transform-origin: 50% 50%;
    transition: stroke-dashoffset 0.5s ease;
}

.notification-toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1rem 1.5rem;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    z-index: 1000;
    display: flex;
    align-items: center;
    gap: 1rem;
    animation: slideInRight 0.4s ease;
    max-width: 350px;
}

@keyframes slideInRight {
    from {
        transform: translateX(100%);
        opacity: 0;
    }

    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.notification-toast.achievement {
    border-color: var(--accent-primary);
    background: linear-gradient(135deg, var(--bg-card), rgba(99, 102, 241, 0.1));
}

.notification-toast.streak {
    border-color: #f59e0b;
    background: linear-gradient(135deg, var(--bg-card), rgba(245, 158, 11, 0.1));
}

.notification-toast.levelup {
    border-color: var(--success);
    background: linear-gradient(135deg, var(--bg-card), rgba(34, 197, 94, 0.1));
}

.notification-icon {
    font-size: 2rem;
}

.notification-content h4 {
    margin: 0 0 0.25rem 0;
    font-size: 1rem;
}

.notification-content p {
    margin: 0;
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Achievements Unlock in Study */
.achievements-unlocked {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(139, 92, 246, 0.1));
    border: 1px solid rgba(99, 102, 241, 0.3);
    border-radius: var(--radius-lg);
    padding: 1rem;
    text-align: left;
}

.achievements-unlocked h4 {
    margin: 0 0 0.75rem 0;
    color: var(--accent-primary);
    font-size: 0.95rem;
}

.achievement-unlock-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.achievement-unlock-item:last-child {
    border-bottom: none;
}

.achievement-unlock-item .achievement-icon {
    width: 32px;
    height: 32px;
    font-size: 1rem;
    background: linear-gradient(135deg, var(--accent-primary), #8b5cf6);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 0;
}

.xp-gained {
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Profile Stats Grid */
.profile-stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-top: 1rem;
}

.profile-stat-section h4 {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.profile-stat-section h4 i {
    color: var(--accent-primary);
}

.profile-stat-item {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

.profile-stat-item:last-child {
    border-bottom: none;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.stat-value {
    font-weight: 600;
    color: var(--text-primary);
}

/* Print */
@media print {

    .navbar,
    .btn,
    .study-actions {
        display: none !important;
    }
}

/* Toast Notifications */
.toast-container {
    position: fixed;
    top: 1rem;
    right: 1rem;
    z-index: 10000;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    max-width: 400px;
    pointer-events: none;
}

.toast {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    pointer-events: auto;
    transform: translateX(120%);
    opacity: 0;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.toast.show {
    transform: translateX(0);
    opacity: 1;
}

.toast.hide {
    transform: translateX(120%);
    opacity: 0;
}

.toast i:first-child {
    font-size: 1.25rem;
    flex-shrink: 0;
}

.toast-message {
    flex: 1;
    font-size: 0.9rem;
    color: var(--text-primary);
}

.toast-close {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 0.25rem;
    font-size: 0.9rem;
    opacity: 0.6;
    transition: opacity var(--transition-fast);
}

.toast-close:hover {
    opacity: 1;
}

.toast-success {
    border-left: 4px solid #22c55e;
}

.toast-success i:first-child {
    color: #22c55e;
}

.toast-danger {
    border-left: 4px solid #ef4444;
}

.toast-danger i:first-child {
    color: #ef4444;
}

.toast-warning {
    border-left: 4px solid #f59e0b;
}

.toast-warning i:first-child {
    color: #f59e0b;
}

.toast-info {
    border-left: 4px solid #3b82f6;
}

.toast-info i:first-child {
    color: #3b82f6;
}

/* Confirm Dialog */
.confirm-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.6);
    backdrop-filter: blur(4px);
    z-index: 10001;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    opacity: 0;
    visibility: hidden;
    transition: all 0.2s ease;
}

.confirm-overlay.active {
    opacity: 1;
    visibility: visible;
}

.confirm-dialog {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: 2rem;
    max-width: 400px;
    width: 100%;
    text-align: center;
    transform: scale(0.9);
    transition: transform 0.2s ease;
}

.confirm-overlay.active .confirm-dialog {
    transform: scale(1);
}

.confirm-icon {
    width: 60px;
    height: 60px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 1.25rem;
    font-size: 1.75rem;
}

.confirm-icon.warning {
    background: rgba(245, 158, 11, 0.15);
    color: #f59e0b;
}

.confirm-icon.danger {
    background: rgba(239, 68, 68, 0.15);
    color: #ef4444;
}

.confirm-icon.info {
    background: rgba(59, 130, 246, 0.15);
    color: #3b82f6;
}

.confirm-icon.success {
    background: rgba(34, 197, 94, 0.15);
    color: #22c55e;
}

.confirm-title {
    margin: 0 0 0.5rem;
    font-size: 1.25rem;
    color: var(--text-primary);
}

.confirm-message {
    margin: 0 0 1.5rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
}

.confirm-actions {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
}

.confirm-actions .btn {
    min-width: 100px;
}

/* Leaderboard */
.leaderboard-container {
    max-width: 800px;
    margin: 0 auto;
}

.leaderboard-header {
    text-align: center;
    margin-bottom: 2rem;
}

.leaderboard-header h1 {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin: 0 0 0.5rem;
}

.leaderboard-header h1 i {
    color: #ffd700;
}

.leaderboard-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.leaderboard-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.leaderboard-item:hover {
    border-color: var(--border-light);
    transform: translateX(4px);
}

.leaderboard-item.top-1 {
    background: linear-gradient(135deg, rgba(255, 215, 0, 0.1), rgba(255, 215, 0, 0.05));
    border-color: rgba(255, 215, 0, 0.3);
}

.leaderboard-item.top-2 {
    background: linear-gradient(135deg, rgba(192, 192, 192, 0.1), rgba(192, 192, 192, 0.05));
    border-color: rgba(192, 192, 192, 0.3);
}

.leaderboard-item.top-3 {
    background: linear-gradient(135deg, rgba(205, 127, 50, 0.1), rgba(205, 127, 50, 0.05));
    border-color: rgba(205, 127, 50, 0.3);
}

.leaderboard-rank {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    border-radius: 50%;
    background: var(--bg-tertiary);
    color: var(--text-muted);
    flex-shrink: 0;
}

.leaderboard-rank i {
    font-size: 1.25rem;
}

.leaderboard-item.top-1 .leaderboard-rank {
    background: rgba(255, 215, 0, 0.15);
    border: 2px solid #ffd700;
}

.leaderboard-item.top-1 .leaderboard-rank i {
    color: #ffd700;
}

.leaderboard-item.top-2 .leaderboard-rank {
    background: rgba(192, 192, 192, 0.15);
    border: 2px solid #c0c0c0;
}

.leaderboard-item.top-2 .leaderboard-rank i {
    color: #c0c0c0;
}

.leaderboard-item.top-3 .leaderboard-rank {
    background: rgba(205, 127, 50, 0.15);
    border: 2px solid #cd7f32;
}

.leaderboard-item.top-3 .leaderboard-rank i {
    color: #cd7f32;
}

.leaderboard-user {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    flex: 1;
    min-width: 0;
}

.leaderboard-avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    color: white;
    font-size: 1.1rem;
    flex-shrink: 0;
}

.leaderboard-name {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.leaderboard-name a {
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.leaderboard-name a:hover {
    color: var(--accent-primary);
}

.leaderboard-username {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.leaderboard-stats {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    flex-shrink: 0;
}

.leaderboard-xp {
    font-weight: 700;
    color: var(--accent-primary);
    font-size: 1.1rem;
}

.leaderboard-level {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.35rem 0.75rem;
    background: var(--bg-tertiary);
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.leaderboard-level i {
    color: #ffd700;
    font-size: 0.75rem;
}

.leaderboard-empty {
    text-align: center;
    padding: 3rem;
    color: var(--text-muted);
}

@media (max-width: 640px) {
    .toast-container {
        left: 1rem;
        right: 1rem;
        max-width: none;
    }

    .toast {
        transform: translateY(-100%);
    }

    .toast.show {
        transform: translateY(0);
    }

    .toast.hide {
        transform: translateY(-100%);
    }

    .leaderboard-stats {
        flex-direction: column;
        gap: 0.5rem;
        align-items: flex-end;
    }
}

/* Category Preview Modal */
.category-preview-modal {
    max-width: 700px;
}

.preview-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.preview-icon {
    width: 50px;
    height: 50px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    color: white;
}

.preview-info h3 {
    margin: 0 0 0.25rem;
}

.preview-meta {
    display: flex;
    align-items: center;
    gap: 1rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.difficulty-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.15rem 0.45rem;
    border-radius: 12px;
    font-size: 0.65rem;
    font-weight: 600;
}

.difficulty-badge i {
    font-size: 0.55rem;
}

.difficulty-badge.easy {
    background: rgba(34, 197, 94, 0.15);
    color: #22c55e;
}

.difficulty-badge.medium {
    background: rgba(245, 158, 11, 0.15);
    color: #f59e0b;
}

.difficulty-badge.hard {
    background: rgba(239, 68, 68, 0.15);
    color: #ef4444;
}

.preview-cards {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    max-height: 400px;
    overflow-y: auto;
}

.preview-card-item {
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
}

.preview-card-question {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.preview-card-answer {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.preview-card-difficulty {
    margin-top: 0.5rem;
    font-size: 0.75rem;
}

/* Toggle Switch */
.toggle-switch {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    cursor: pointer;
    user-select: none;
}

.toggle-switch input {
    display: none;
}

.toggle-slider {
    position: relative;
    width: 48px;
    height: 26px;
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 26px;
    transition: all var(--transition-fast);
    flex-shrink: 0;
}

.toggle-slider::before {
    content: '';
    position: absolute;
    top: 2px;
    left: 2px;
    width: 18px;
    height: 18px;
    background: var(--text-muted);
    border-radius: 50%;
    transition: all var(--transition-fast);
}

.toggle-switch input:checked+.toggle-slider {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
}

.toggle-switch input:checked+.toggle-slider::before {
    transform: translateX(22px);
    background: white;
}

.toggle-label {
    font-size: 0.95rem;
    color: var(--text-primary);
}

/* Leaderboard Promo */
.leaderboard-promo {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: linear-gradient(135deg, rgba(255, 215, 0, 0.1), rgba(245, 158, 11, 0.05));
    border: 1px solid rgba(255, 215, 0, 0.3);
    border-radius: var(--radius-lg);
    text-decoration: none;
    transition: all var(--transition-fast);
}

.leaderboard-promo:hover {
    border-color: rgba(255, 215, 0, 0.5);
    transform: translateY(-2px);
}

.leaderboard-promo .promo-content {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.leaderboard-promo .promo-content>i {
    font-size: 1.75rem;
    color: #ffd700;
}

.leaderboard-promo .promo-content strong {
    display: block;
    color: var(--text-primary);
    margin-bottom: 0.15rem;
}

.leaderboard-promo .promo-content p {
    margin: 0;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.leaderboard-promo.leaderboard-promo-active {
    cursor: pointer;
}

.leaderboard-promo.leaderboard-promo-active>i {
    color: var(--text-muted);
    transition: transform var(--transition-fast);
}

.leaderboard-promo.leaderboard-promo-active:hover>i {
    transform: translateX(4px);
    color: #ffd700;
}

/* Native Color Input */
.color-input {
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;
    width: 60px;
    height: 40px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: transparent;
    cursor: pointer;
    padding: 0;
}

.color-input::-webkit-color-swatch-wrapper {
    padding: 4px;
}

.color-input::-webkit-color-swatch {
    border: none;
    border-radius: calc(var(--radius-md) - 4px);
}

.color-input::-moz-color-swatch {
    border: none;
    border-radius: calc(var(--radius-md) - 4px);
}

.color-input:hover {
    border-color: var(--accent-primary);
}

.color-input:focus {
    outline: none;
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.2);
}

/* System Badge - Diamond Style */
.system-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 18px;
    height: 18px;
    border-radius: 4px;
    background: rgba(245, 158, 11, 0.15);
    color: #f59e0b;
    font-size: 0.6rem;
    border: 1px solid rgba(245, 158, 11, 0.3);
}

.system-badge.badge-sm {
    width: 14px;
    height: 14px;
    font-size: 0.45rem;
}

.system-badge-full {
    display: inline-flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.3rem 0.75rem;
    background: rgba(245, 158, 11, 0.15);
    border: 1px solid rgba(245, 158, 11, 0.3);
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
    color: #f59e0b;
}

.system-badge-full i {
    font-size: 0.75rem;
}

/* Activity Feed */
.feed-page {
    max-width: 700px;
    margin: 0 auto;
}

.feed-header {
    text-align: center;
    margin-bottom: 2rem;
}

.feed-header h1 {
    margin-bottom: 0.5rem;
}

.feed-tabs {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 0.5rem;
}

.feed-tab {
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    color: var(--text-muted);
    text-decoration: none;
    transition: all var(--transition-fast);
}

.feed-tab:hover {
    color: var(--text-primary);
    background: var(--bg-tertiary);
}

.feed-tab.active {
    color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.1);
}

.feed-empty {
    text-align: center;
    padding: 3rem;
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.feed-empty .empty-icon {
    font-size: 3rem;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.feed-empty h3 {
    margin-bottom: 0.5rem;
}

.feed-empty p {
    color: var(--text-muted);
    margin-bottom: 1.5rem;
}

.feed-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.feed-item {
    display: flex;
    gap: 1rem;
    padding: 1.25rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
}

.feed-item:hover {
    border-color: var(--accent-primary);
}

.feed-item-avatar {
    flex-shrink: 0;
}

.feed-item-avatar a {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    color: white;
    text-decoration: none;
}

.feed-item-content {
    flex: 1;
    min-width: 0;
}

.feed-item-header {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
}

.feed-item-name {
    font-weight: 600;
    color: var(--text-primary);
    text-decoration: none;
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.feed-item-name:hover {
    color: var(--accent-primary);
}

.feed-item-time {
    color: var(--text-muted);
    font-size: 0.85rem;
}

.feed-item-body {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--text-secondary);
    margin-bottom: 0.75rem;
}

.feed-item-icon {
    color: var(--accent-primary);
    font-size: 1.1rem;
}

.feed-item-actions {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.reaction-buttons {
    display: flex;
    gap: 0.25rem;
}

.reaction-btn {
    display: flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.35rem 0.6rem;
    border-radius: 20px;
    border: 1px solid var(--border-color);
    background: transparent;
    color: var(--text-muted);
    font-size: 0.85rem;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.reaction-btn:hover {
    border-color: var(--accent-primary);
    color: var(--text-primary);
    background: rgba(99, 102, 241, 0.1);
}

.reaction-btn.active {
    border-color: var(--accent-primary);
    background: rgba(99, 102, 241, 0.15);
    color: var(--accent-primary);
}

.reaction-btn i {
    font-size: 0.9rem;
}

.reaction-count {
    font-weight: 600;
    font-size: 0.8rem;
}

.reaction-count:empty {
    display: none;
}

/* Follow Button */
.follow-btn {
    min-width: 100px;
}

.follow-btn.following {
    background: var(--bg-tertiary);
    border-color: var(--border-color);
    color: var(--text-secondary);
}

.follow-btn.following:hover {
    background: rgba(239, 68, 68, 0.1);
    border-color: var(--danger);
    color: var(--danger);
}

.follow-btn.following:hover .follow-text {
    display: none;
}

.follow-btn.following:hover .unfollow-text {
    display: inline;
}

.follow-btn .unfollow-text {
    display: none;
}

/* Follow Stats */
.follow-stats {
    display: flex;
    gap: 1.5rem;
    margin-top: 0.75rem;
}

.follow-stat {
    text-align: center;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: var(--radius-md);
    transition: background var(--transition-fast);
}

.follow-stat:hover {
    background: var(--bg-tertiary);
}

.follow-stat-count {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
    display: block;
}

.follow-stat-label {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* Responsive */
@media (max-width: 640px) {
    .feed-item {
        flex-direction: column;
        gap: 0.75rem;
    }

    .feed-item-avatar {
        display: flex;
        align-items: center;
        gap: 0.75rem;
    }

    .reaction-buttons {
        flex-wrap: wrap;
    }
}

/* Follow List Modal */
.follow-list-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    border-radius: var(--radius-md);
    text-decoration: none;
    color: inherit;
    transition: background var(--transition-fast);
}

.follow-list-item:hover {
    background: var(--bg-tertiary);
}

.follow-list-avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--accent-gradient);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1rem;
    color: white;
    flex-shrink: 0;
}

.follow-list-info {
    flex: 1;
    min-width: 0;
}

.follow-list-name {
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.follow-list-username {
    font-size: 0.85rem;
    color: var(--text-muted);
}

.empty-state-sm {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
}

.empty-state-sm i {
    font-size: 2rem;
    margin-bottom: 0.5rem;
    display: block;
}

.loading-spinner {
    text-align: center;
    padding: 2rem;
    color: var(--text-muted);
}

/* Notification Settings */
.notification-settings {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    margin-top: 1.5rem;
}

.notification-settings h3 {
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.notification-setting-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 0;
    border-bottom: 1px solid var(--border-color);
}

.notification-setting-item:last-child {
    border-bottom: none;
}

.notification-setting-info {
    flex: 1;
}

.notification-setting-title {
    font-weight: 500;
    color: var(--text-primary);
}

.notification-setting-desc {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
}

/* Navigation Notification Badge on Profile */
.nav-link-profile {
    position: relative;
}

.nav-link-profile .nav-notification-badge {
    position: absolute;
    top: -2px;
    right: -8px;
    min-width: 16px;
    height: 16px;
    padding: 0 4px;
    background: var(--danger);
    color: white;
    font-size: 0.65rem;
    font-weight: 700;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    animation: pulse-badge 2s infinite;
}

@keyframes pulse-badge {
    0%, 100% {
        transform: scale(1);
    }

    50% {
        transform: scale(1.1);
    }
}

/* Notifications Page */
.notifications-page {
    max-width: 700px;
    margin: 0 auto;
}

.notifications-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.notifications-header h1 {
    margin: 0;
}

.notifications-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.notification-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    cursor: pointer;
}

.notification-item:hover {
    border-color: var(--accent-primary);
}

.notification-item.unread {
    background: rgba(99, 102, 241, 0.05);
    border-color: rgba(99, 102, 241, 0.3);
}

.notification-icon {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    color: var(--accent-primary);
    font-size: 1.1rem;
}

.notification-item.unread .notification-icon {
    background: var(--accent-gradient);
    color: white;
}

.notification-content {
    flex: 1;
    min-width: 0;
}

.notification-title {
    font-weight: 600;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.notification-badge {
    font-size: 0.65rem;
    padding: 0.15rem 0.4rem;
    background: var(--accent-primary);
    color: white;
    border-radius: 4px;
    font-weight: 700;
    text-transform: uppercase;
}

.notification-message {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-top: 0.25rem;
}

.notification-time {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.35rem;
}

.notification-link {
    color: var(--text-muted);
    padding: 0.5rem;
    transition: color var(--transition-fast);
}

.notification-link:hover {
    color: var(--accent-primary);
}

@media (max-width: 640px) {
    .notifications-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* Notification Quick Link on Profile */
.notification-quick-link {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    color: var(--text-secondary);
}

.notification-quick-link:hover {
    border-color: var(--accent-primary);
    color: var(--text-primary);
}

.notification-quick-link.has-notifications {
    border-color: rgba(99, 102, 241, 0.3);
    background: rgba(99, 102, 241, 0.05);
}

.notification-quick-icon {
    position: relative;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--bg-tertiary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: var(--text-muted);
    flex-shrink: 0;
}

.notification-quick-link.has-notifications .notification-quick-icon {
    background: var(--accent-gradient);
    color: white;
}

.notification-quick-badge {
    position: absolute;
    top: -4px;
    right: -4px;
    min-width: 18px;
    height: 18px;
    padding: 0 5px;
    background: var(--danger);
    color: white;
    font-size: 0.7rem;
    font-weight: 700;
    border-radius: 9px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.notification-quick-text {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
}

.notification-quick-text strong {
    color: var(--text-primary);
    font-weight: 600;
}

.notification-quick-text span {
    font-size: 0.85rem;
}

.notification-quick-link>i:last-child {
    color: var(--text-muted);
}

/* Study Page Mobile Fixes */
@media (max-width: 640px) {
    body {
        overflow-x: hidden;
    }
    
    .study-container {
        padding: 0.5rem;
        overflow-x: hidden;
    }

    .study-header {
        padding: 0 0.25rem;
        margin-bottom: 1rem;
        gap: 0.5rem;
    }

    .study-header .btn {
        padding: 0.5rem 0.75rem;
        font-size: 0.85rem;
    }

    .progress-bar {
        width: 100px;
    }

    .progress-text {
        font-size: 0.8rem;
    }

    .swipe-indicators {
        margin-bottom: 0.75rem;
    }

    .swipe-indicator-icon {
        width: 40px;
        height: 40px;
        font-size: 1.2rem;
    }

    .swipe-indicator span {
        font-size: 0.7rem;
    }

    .flashcard-stack {
        height: 320px;
        margin-bottom: 1rem;
    }

    .flashcard {
        padding: 1.25rem;
    }

    .study-actions {
        gap: 0.75rem;
    }

    .action-btn {
        width: 56px;
        height: 56px;
        font-size: 1.25rem;
    }
}
/* =====================================================
   HEATMAP CALENDAR
   ===================================================== */

.heatmap-container {
    overflow-x: auto;
    padding-bottom: 0.5rem;
}

.heatmap-grid {
    display: grid;
    grid-template-rows: repeat(7, 1fr);
    grid-auto-flow: column;
    gap: 4px;
    width: fit-content;
}

.heatmap-cell {
    width: 14px;
    height: 14px;
    border-radius: 3px;
    background: var(--bg-tertiary);
    transition: transform 0.1s, box-shadow 0.1s;
}

.heatmap-cell:hover {
    transform: scale(1.2);
    z-index: 1;
    box-shadow: 0 0 8px rgba(99, 102, 241, 0.5);
}

.heatmap-cell.intensity-0 { background: var(--bg-tertiary); }
.heatmap-cell.intensity-1 { background: rgba(99, 102, 241, 0.3); }
.heatmap-cell.intensity-2 { background: rgba(99, 102, 241, 0.5); }
.heatmap-cell.intensity-3 { background: rgba(99, 102, 241, 0.75); }
.heatmap-cell.intensity-4 { background: var(--primary); box-shadow: 0 0 4px rgba(99, 102, 241, 0.3); }

.heatmap-legend {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    margin-top: 1rem;
    font-size: 0.75rem;
}

.heatmap-legend .heatmap-cell {
    width: 12px;
    height: 12px;
}

.heatmap-legend .heatmap-cell:hover {
    transform: none;
    box-shadow: none;
}

@media (max-width: 768px) {
    .heatmap-cell {
        width: 10px;
        height: 10px;
    }
    .heatmap-grid {
        gap: 2px;
    }
}

/* =====================================================
   STUDY GROUPS
   ===================================================== */

.group-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 1.5rem;
    transition: all var(--transition-fast);
}

.group-card:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

.group-card-header {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1rem;
}

.group-icon {
    width: 50px;
    height: 50px;
    background: var(--accent-gradient);
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.3rem;
    flex-shrink: 0;
}

.group-info {
    flex: 1;
    min-width: 0;
}

.group-info h3 {
    margin: 0 0 0.25rem;
    font-size: 1.1rem;
}

.group-info p {
    margin: 0;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.group-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}

.group-meta span {
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.group-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.invite-code-display {
    background: var(--bg-tertiary);
    padding: 1rem;
    border-radius: var(--radius);
    text-align: center;
    font-family: monospace;
    font-size: 1.5rem;
    letter-spacing: 3px;
    color: var(--primary);
    border: 2px dashed var(--border-color);
}

.invite-code-display small {
    display: block;
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-top: 0.5rem;
    letter-spacing: normal;
    font-family: var(--font-primary);
}

.member-list {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.member-item {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 0.75rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius);
}

.member-avatar {
    width: 40px;
    height: 40px;
    background: var(--accent-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 600;
    flex-shrink: 0;
}

.member-info {
    flex: 1;
    min-width: 0;
}

.member-info .name {
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.member-info .role {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.role-badge {
    font-size: 0.7rem;
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-weight: 600;
}

.role-badge.owner {
    background: var(--warning);
    color: #000;
}

.role-badge.admin {
    background: var(--primary);
    color: white;
}

.groups-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.5rem;
}

@media (max-width: 768px) {
    .groups-grid {
        grid-template-columns: 1fr;
    }
    
    .group-card-header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .group-icon {
        width: 40px;
        height: 40px;
        font-size: 1.1rem;
    }
}

/* Category Icon Badge */
.category-header-content {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.category-icon-badge {
    width: 40px;
    height: 40px;
    border-radius: var(--radius);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1rem;
    flex-shrink: 0;
}

/* Icon Picker (for categories form) */
.icon-picker-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(44px, 1fr));
    gap: 0.5rem;
    padding: 1rem;
    background: var(--bg-tertiary);
    border-radius: var(--radius);
    max-height: 240px;
    overflow-y: auto;
}

.icon-picker-item {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border: 2px solid transparent;
    border-radius: var(--radius);
    cursor: pointer;
    font-size: 1.1rem;
    color: var(--text-muted);
    transition: all 0.15s ease;
}

.icon-picker-item:hover {
    border-color: var(--border-color);
    color: var(--text-primary);
    transform: scale(1.1);
}

.icon-picker-item.selected {
    border-color: var(--primary);
    background: var(--primary);
    color: white;
}

/* ================================
   PROFILE PAGE STYLES
   ================================ */
.profile-page { max-width: 900px; margin: 0 auto; }
.profile-edit-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 1.5rem; }

/* Profile Header */
.profile-header-card { display: flex; justify-content: space-between; align-items: flex-start; gap: 1rem; padding: 1.5rem; background: var(--bg-secondary); border: 1px solid var(--border-color); border-radius: var(--radius-lg); margin-bottom: 1.5rem; }
.profile-header-left { display: flex; gap: 1.25rem; align-items: center; }
.profile-avatar-wrapper { position: relative; }
.profile-avatar-lg { width: 80px; height: 80px; background: var(--accent-gradient); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 2rem; font-weight: 600; color: white; }
.profile-level-badge { position: absolute; bottom: -6px; left: 50%; transform: translateX(-50%); display: flex; align-items: center; gap: 0.25rem; padding: 0.2rem 0.5rem; border-radius: 12px; font-size: 0.75rem; font-weight: 600; white-space: nowrap; border: 2px solid var(--bg-secondary); }
.profile-level-badge.tier-bronze { background: #cd7f32; color: white; }
.profile-level-badge.tier-silver { background: #c0c0c0; color: #333; }
.profile-level-badge.tier-gold { background: linear-gradient(135deg, #f5af19, #f12711); color: white; }
.profile-level-badge.tier-diamond { background: linear-gradient(135deg, #667eea, #764ba2); color: white; }
.profile-name { margin: 0; font-size: 1.5rem; display: flex; align-items: center; gap: 0.5rem; }
.profile-username { margin: 0.25rem 0 0; color: var(--text-muted); }
.profile-meta { display: flex; align-items: center; gap: 1rem; margin-top: 0.5rem; }
.profile-header-actions { display: flex; gap: 0.5rem; }
.btn-notif-badge { background: var(--danger); color: white; font-size: 0.65rem; padding: 0.1rem 0.35rem; border-radius: 10px; margin-left: 0.25rem; }

/* Profile Tabs */
.profile-tabs { display: flex; gap: 0.5rem; margin-bottom: 1.5rem; background: var(--bg-tertiary); padding: 0.35rem; border-radius: var(--radius-lg); }
.profile-tab { flex: 1; display: flex; align-items: center; justify-content: center; gap: 0.5rem; padding: 0.75rem 1rem; border-radius: var(--radius-lg); color: var(--text-muted); text-decoration: none; font-weight: 500; transition: all 0.2s; }
.profile-tab:hover { color: var(--text-primary); background: rgba(255,255,255,0.05); }
.profile-tab.active { background: var(--accent-gradient); color: white; }

/* Profile Stats Grid */
.profile-stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }
.profile-stat-card { background: var(--bg-secondary); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.25rem; text-align: center; }
.profile-stat-card .stat-icon { width: 44px; height: 44px; border-radius: 50%; display: flex; align-items: center; justify-content: center; margin: 0 auto 0.75rem; font-size: 1.1rem; }
.profile-stat-card .stat-icon.purple { background: rgba(139, 92, 246, 0.15); color: #8b5cf6; }
.profile-stat-card .stat-icon.green { background: rgba(34, 197, 94, 0.15); color: #22c55e; }
.profile-stat-card .stat-icon.orange { background: rgba(249, 115, 22, 0.15); color: #f97316; }
.profile-stat-card .stat-icon.blue { background: rgba(59, 130, 246, 0.15); color: #3b82f6; }
.profile-stat-card .stat-value { font-size: 1.5rem; font-weight: 700; }
.profile-stat-card .stat-label { font-size: 0.8rem; color: var(--text-muted); margin-top: 0.25rem; }

/* Profile Achievements */
.profile-achievements-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(140px, 1fr)); gap: 0.75rem; }
.profile-achievement-item { display: flex; flex-direction: column; align-items: center; gap: 0.35rem; padding: 1rem 0.75rem; background: var(--bg-tertiary); border-radius: var(--radius-lg); opacity: 0.4; transition: opacity 0.2s; text-align: center; }
.profile-achievement-item.earned { opacity: 1; }
.profile-ach-icon { width: 40px; height: 40px; background: var(--bg-secondary); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 1.1rem; }
.profile-achievement-item.earned .profile-ach-icon { background: var(--accent-gradient); color: white; }
.profile-ach-name { font-size: 0.85rem; font-weight: 600; color: var(--text-primary); }
.profile-ach-desc { font-size: 0.7rem; color: var(--text-muted); line-height: 1.3; }
.profile-ach-xp { font-size: 0.7rem; font-weight: 600; color: var(--primary); background: rgba(99, 102, 241, 0.1); padding: 0.15rem 0.5rem; border-radius: 10px; }

/* Profile Feed */
.profile-feed-list { display: flex; flex-direction: column; gap: 0.75rem; }
.profile-feed-item { display: flex; gap: 1rem; padding: 1rem; background: var(--bg-secondary); border: 1px solid var(--border-color); border-radius: var(--radius-lg); }
.profile-feed-avatar { width: 44px; height: 44px; background: var(--accent-gradient); border-radius: 50%; display: flex; align-items: center; justify-content: center; color: white; font-weight: 600; text-decoration: none; flex-shrink: 0; }
.profile-feed-content { flex: 1; min-width: 0; }
.profile-feed-header { display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; }
.profile-feed-author { font-weight: 600; color: inherit; text-decoration: none; display: flex; align-items: center; gap: 0.35rem; }
.profile-feed-time { font-size: 0.8rem; color: var(--text-muted); }
.profile-feed-body { margin-top: 0.25rem; }

/* Profile Groups */
.profile-btn-group { display: flex; gap: 0.5rem; }
.profile-groups-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 1rem; }
.profile-group-card { display: block; background: var(--bg-secondary); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.25rem; text-decoration: none; color: inherit; transition: all 0.2s; }
.profile-group-card:hover { border-color: var(--primary); transform: translateY(-2px); }
.profile-group-header { display: flex; gap: 0.75rem; margin-bottom: 0.75rem; }
.profile-group-icon { width: 44px; height: 44px; background: var(--accent-gradient); border-radius: var(--radius); display: flex; align-items: center; justify-content: center; color: white; flex-shrink: 0; }
.profile-group-info { flex: 1; min-width: 0; }
.profile-group-info h4 { margin: 0 0 0.25rem; font-size: 1rem; }
.profile-group-info p { margin: 0; font-size: 0.85rem; color: var(--text-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.profile-group-meta { display: flex; gap: 0.75rem; font-size: 0.85rem; color: var(--text-muted); flex-wrap: wrap; }
.profile-group-meta span { display: flex; align-items: center; gap: 0.3rem; }

/* Profile Modal */
.profile-modal { display: none; position: fixed; top: 0; left: 0; right: 0; bottom: 0; z-index: 1000; align-items: center; justify-content: center; }
.profile-modal.active { display: flex; }
.profile-modal-backdrop { position: fixed; top: 0; left: 0; right: 0; bottom: 0; background: rgba(0,0,0,0.7); z-index: 1001; }
.profile-modal-content { position: relative; z-index: 1002; background: var(--bg-secondary); border: 1px solid var(--border-color); border-radius: var(--radius-lg); padding: 1.5rem; width: 100%; max-width: 450px; margin: 1rem; box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5); }
.profile-modal-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 1.25rem; padding-bottom: 1rem; border-bottom: 1px solid var(--border-color); }
.profile-modal-header h3 { margin: 0; }
.profile-modal-close { background: none; border: none; font-size: 1.5rem; cursor: pointer; color: var(--text-muted); line-height: 1; padding: 0; width: 32px; height: 32px; display: flex; align-items: center; justify-content: center; border-radius: var(--radius); transition: all 0.2s; }
.profile-modal-close:hover { color: var(--text-primary); background: var(--bg-tertiary); }
.profile-invite-input { text-transform: uppercase; letter-spacing: 4px; text-align: center; font-size: 1.25rem; font-family: monospace; font-weight: 600; }

/* Profile Responsive */
@media (max-width: 768px) {
    .profile-header-card { flex-direction: column; }
    .profile-header-left { flex-direction: column; text-align: center; }
    .profile-meta { justify-content: center; }
    .profile-header-actions { width: 100%; justify-content: center; }
    .profile-stats-grid { grid-template-columns: repeat(2, 1fr); }
    .profile-tab { padding: 0.6rem 0.5rem; font-size: 0.85rem; }
    .profile-tab span { display: none; }
    .profile-achievements-grid { grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); }
    .profile-achievement-item { padding: 0.75rem 0.5rem; }
    .profile-ach-desc { font-size: 0.65rem; }
}

/* Feed Subtabs */
.feed-subtabs {
    display: flex;
    gap: 0.5rem;
    background: var(--bg-tertiary);
    padding: 0.25rem;
    border-radius: var(--radius);
}

.feed-subtab {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius);
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    transition: all 0.2s;
}

.feed-subtab:hover {
    color: var(--text-primary);
    background: rgba(255,255,255,0.05);
}

.feed-subtab.active {
    background: var(--bg-secondary);
    color: var(--text-primary);
}

/* Admin User Table Improvements */
.row-banned {
    opacity: 0.6;
}

.user-cell {
    display: flex;
    flex-direction: column;
    gap: 0.15rem;
}

.user-name {
    text-decoration: none;
    color: inherit;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.user-name:hover {
    color: var(--primary);
}

.user-username {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.email-cell {
    display: flex;
    align-items: center;
    gap: 0.35rem;
}

.stat-mini {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-right: 0.75rem;
}

.stat-mini i {
    font-size: 0.75rem;
}

.action-buttons {
    display: flex;
    gap: 0.25rem;
    flex-wrap: wrap;
}

.badge-sm {
    font-size: 0.65rem !important;
    padding: 0.1rem 0.3rem !important;
}

.badge-secondary {
    background: var(--bg-tertiary);
    color: var(--text-muted);
}

/* Activity Chart */
.activity-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.activity-summary {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-align: right;
}

.activity-total {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.activity-change {
    display: inline-flex;
    align-items: center;
    gap: 0.2rem;
    padding: 0.2rem 0.5rem;
    border-radius: var(--radius);
    font-size: 0.75rem;
    font-weight: 600;
}

.activity-change.positive {
    background: rgba(34, 197, 94, 0.15);
    color: #22c55e;
}

.activity-change.negative {
    background: rgba(239, 68, 68, 0.15);
    color: #ef4444;
}

.activity-line-chart {
    position: relative;
    margin-top: 1rem;
}

.activity-svg {
    width: 100%;
    height: auto;
    display: block;
}

.activity-line {
    filter: drop-shadow(0 2px 4px rgba(99, 102, 241, 0.3));
}

.activity-point {
    cursor: pointer;
    transition: all 0.2s ease;
}

.activity-point:hover {
    r: 6;
    filter: drop-shadow(0 0 6px #6366f1);
}

.activity-tooltip {
    position: absolute;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-light);
    border-radius: 8px;
    padding: 0.5rem 0.75rem;
    font-size: 0.75rem;
    color: var(--text-primary);
    pointer-events: none;
    opacity: 0;
    transition: opacity 0.2s ease;
    transform: translateX(-50%);
    z-index: 10;
    white-space: nowrap;
    box-shadow: var(--shadow-md);
}

.activity-tooltip::after {
    content: '';
    position: absolute;
    bottom: -6px;
    left: 50%;
    transform: translateX(-50%);
    border-left: 6px solid transparent;
    border-right: 6px solid transparent;
    border-top: 6px solid var(--bg-tertiary);
}

@media (max-width: 640px) {
    .activity-header {
        flex-direction: column;
        gap: 0.5rem;
    }
    
    .activity-summary {
        width: 100%;
        justify-content: flex-start;
    }
}

/* Markdown Content Styling */
.markdown-content {
    line-height: 1.6;
}

.markdown-content p {
    margin: 0 0 0.75em 0;
}

.markdown-content p:last-child {
    margin-bottom: 0;
}

.markdown-content h2,
.markdown-content h3,
.markdown-content h4 {
    margin: 0.5em 0 0.25em 0;
    font-weight: 600;
    line-height: 1.3;
}

.markdown-content h2 { font-size: 1.3em; }
.markdown-content h3 { font-size: 1.15em; }
.markdown-content h4 { font-size: 1em; }

.markdown-content strong {
    font-weight: 600;
    color: var(--text-primary);
}

.markdown-content em {
    font-style: italic;
}

.markdown-content del {
    text-decoration: line-through;
    opacity: 0.7;
}

.markdown-content code {
    background: rgba(99, 102, 241, 0.15);
    color: #a5b4fc;
    padding: 0.15em 0.4em;
    border-radius: 4px;
    font-family: 'SF Mono', 'Fira Code', 'Monaco', 'Consolas', monospace;
    font-size: 0.9em;
}

.markdown-content pre {
    background: var(--bg-tertiary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1rem;
    overflow-x: auto;
    margin: 0.75em 0;
}

.markdown-content pre code {
    background: none;
    padding: 0;
    color: var(--text-primary);
    font-size: 0.85em;
    line-height: 1.5;
}

.markdown-content blockquote {
    border-left: 3px solid var(--primary);
    margin: 0.75em 0;
    padding: 0.5em 0 0.5em 1em;
    background: rgba(99, 102, 241, 0.05);
    border-radius: 0 var(--radius) var(--radius) 0;
    color: var(--text-muted);
    font-style: italic;
}

.markdown-content ul,
.markdown-content ol {
    margin: 0.5em 0;
    padding-left: 1.5em;
}

.markdown-content li {
    margin: 0.25em 0;
}

.markdown-content ul li::marker {
    color: var(--primary);
}

.markdown-content ol li::marker {
    color: var(--primary);
    font-weight: 600;
}

.markdown-content hr {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 1em 0;
}

.markdown-content a {
    color: var(--primary);
    text-decoration: none;
}

.markdown-content a:hover {
    text-decoration: underline;
}

/* Flashcard specific markdown adjustments */
.flashcard-question.markdown-content,
.flashcard-answer.markdown-content {
    text-align: left;
}

.flashcard-question.markdown-content p,
.flashcard-answer.markdown-content p {
    text-align: center;
}

.flashcard-question.markdown-content pre,
.flashcard-question.markdown-content blockquote,
.flashcard-question.markdown-content ul,
.flashcard-question.markdown-content ol,
.flashcard-answer.markdown-content pre,
.flashcard-answer.markdown-content blockquote,
.flashcard-answer.markdown-content ul,
.flashcard-answer.markdown-content ol {
    text-align: left;
}