/* ===== CSS RESET & BASE ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Prevent images and media from causing overflow */
img,
video,
iframe,
embed,
object {
    max-width: 100%;
    height: auto;
}

/* Prevent long words from causing overflow */
p,
h1,
h2,
h3,
h4,
h5,
h6,
li,
span,
a {
    overflow-wrap: break-word;
    word-wrap: break-word;
}

:root {
    /* Blue Theme Colors */
    --primary-blue: #0066FF;
    --primary-blue-dark: #0052CC;
    --primary-blue-light: #3385FF;
    --accent-cyan: #00D4FF;
    --accent-purple: #6B5FFF;
    --youtube-red: #ff0000;

    /* Neutral Colors */
    --bg-primary: #0A0E1A;
    --bg-secondary: #111827;
    --bg-tertiary: #1F2937;
    --surface: rgba(17, 24, 39, 0.8);
    --surface-glass: rgba(17, 24, 39, 0.6);

    /* Text Colors */
    --text-primary: #F9FAFB;
    --text-secondary: #D1D5DB;
    --text-muted: #9CA3AF;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--primary-blue), var(--accent-cyan));
    --gradient-secondary: linear-gradient(135deg, var(--accent-purple), var(--primary-blue));
    --gradient-mesh: radial-gradient(circle at 20% 50%, rgba(0, 102, 255, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(107, 95, 255, 0.1) 0%, transparent 50%);

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 102, 255, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 102, 255, 0.15);
    --shadow-lg: 0 8px 32px rgba(0, 102, 255, 0.2);
    --shadow-glow: 0 0 30px rgba(0, 102, 255, 0.3);

    /* Typography */
    --font-primary: 'Inter', sans-serif;
    --font-display: 'Space Grotesk', sans-serif;
    --font-mono: 'Consolas', 'Monaco', monospace;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;

    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-base: 0.3s ease;
}

/* Light Theme */
[data-theme="light"] {
    --primary-blue: #0052CC;
    --primary-blue-dark: #003d99;
    --primary-blue-light: #3385FF;
    --accent-cyan: #0099CC;
    --youtube-red: #ff0000;

    --bg-primary: #F5F7FA;
    --bg-secondary: #FFFFFF;
    --bg-tertiary: #E9ECF1;
    --surface: rgba(255, 255, 255, 0.8);
    --surface-glass: rgba(255, 255, 255, 0.6);

    --text-primary: #1A1A1A;
    --text-secondary: #4A5568;
    --text-muted: #718096;

    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 16px rgba(0, 82, 204, 0.1);
    --shadow-lg: 0 8px 32px rgba(0, 82, 204, 0.15);
    --shadow-glow: 0 0 30px rgba(0, 82, 204, 0.2);
}

html {
    scroll-behavior: smooth;
    overflow-x: hidden;
    width: 100%;
}

body {
    font-family: var(--font-primary);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    width: 100%;
    max-width: 100vw;
    position: relative;
}

/* ===== BACKGROUND ELEMENTS ===== */
.bg-gradient {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--gradient-mesh);
    z-index: -2;
    pointer-events: none;
    overflow: hidden;
}

.grid-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-image:
        linear-gradient(rgba(0, 102, 255, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 102, 255, 0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    z-index: -1;
    pointer-events: none;
    overflow: hidden;
}

/* ===== NAVIGATION ===== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    max-width: 100vw;
    padding: var(--spacing-md) 0;
    background: var(--surface-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 102, 255, 0.1);
    z-index: 1000;
    transition: var(--transition-base);
    overflow-x: hidden;
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo-container {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    flex-shrink: 1;
    min-width: 0;
}

.logo-text {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    flex-shrink: 1;
    min-width: 0;
}

.nav-logo {
    height: 40px;
    width: auto;
    filter: drop-shadow(0 0 10px rgba(0, 102, 255, 0.3));
    transition: var(--transition-base);
}

.nav-logo:hover {
    filter: drop-shadow(0 0 20px rgba(0, 102, 255, 0.5));
    transform: scale(1.05);
}

.nav-actions {
    display: flex;
    gap: var(--spacing-sm);
    align-items: center;
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 0.95rem;
    text-decoration: none;
    transition: all var(--transition-base);
    cursor: pointer;
    border: none;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-youtube {
    background: var(--youtube-red);
    color: white;
    box-shadow: 0 4px 16px rgba(255, 0, 0, 0.25);
    transition: var(--transition-base);
}

.btn-youtube:hover {
    background: #cc0000;
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(255, 0, 0, 0.35);
}

.btn-secondary {
    background: var(--surface);
    color: var(--text-primary);
    border: 1px solid rgba(0, 102, 255, 0.3);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    border-color: var(--primary-blue);
    background: rgba(0, 102, 255, 0.1);
}

.btn-large {
    padding: 1.25rem 2.5rem;
    font-size: 1.125rem;
}

.btn-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: var(--surface);
    border: 1px solid rgba(0, 102, 255, 0.2);
    border-radius: var(--radius-md);
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--transition-base);
}

.btn-icon:hover {
    background: rgba(0, 102, 255, 0.1);
    border-color: var(--primary-blue);
    color: var(--primary-blue);
}

.theme-toggle {
    transition: var(--transition-base);
}

[data-theme="light"] .theme-toggle .sun-icon {
    display: none;
}

[data-theme="light"] .theme-toggle .moon-icon {
    display: block !important;
}

/* ===== MAIN CONTAINER ===== */
.main-container {
    display: flex;
    padding-top: 80px;
    min-height: 100vh;
    max-width: 100vw;
    overflow-x: hidden;
    width: 100%;
}

/* ===== SIDEBAR ===== */
.sidebar {
    width: 260px;
    min-width: 260px;
    background: var(--surface-glass);
    backdrop-filter: blur(20px);
    border-right: 1px solid rgba(0, 102, 255, 0.1);
    padding: var(--spacing-md);
    overflow-y: auto;
    overflow-x: hidden;
    height: calc(100vh - 80px);
    position: sticky;
    top: 80px;
    transition: var(--transition-base);
}

.sidebar.minimized {
    width: 60px;
    min-width: 60px;
    padding: var(--spacing-sm);
    overflow: hidden;
}

.sidebar.minimized .sidebar-title,
.sidebar.minimized .search-box,
.sidebar.minimized .video-info,
.sidebar.minimized .empty-state .empty-title,
.sidebar.minimized .empty-state .empty-text,
.sidebar.minimized .video-item-content {
    display: none !important;
}

.sidebar.minimized .video-item {
    justify-content: center;
    align-items: center;
    padding: 0.65rem;
    min-height: 48px;
    overflow: hidden;
}

.sidebar.minimized .video-item-icon {
    margin: 0;
    opacity: 1;
}

.sidebar-header {
    margin-bottom: var(--spacing-md);
}

.sidebar-header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.sidebar-toggle {
    opacity: 0.7;
    transition: var(--transition-fast);
}

.sidebar-toggle:hover {
    opacity: 1;
    background: rgba(0, 102, 255, 0.1);
}

.sidebar-title {
    font-family: var(--font-display);
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0;
}

.search-box {
    position: relative;
}

.search-icon {
    position: absolute;
    left: var(--spacing-sm);
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
}

.search-input {
    width: 100%;
    padding: 0.75rem var(--spacing-sm) 0.75rem 2.5rem;
    background: var(--bg-tertiary);
    border: 1px solid rgba(0, 102, 255, 0.2);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: var(--transition-base);
}

.search-input:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

.video-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.video-item {
    display: flex;
    align-items: center;
    gap: 0.65rem;
    padding: 0.65rem;
    background: var(--bg-tertiary);
    border: 1px solid rgba(0, 102, 255, 0.08);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition-base);
    margin-bottom: 0.5rem;
}

.video-item-icon {
    font-size: 1.25rem;
    flex-shrink: 0;
    opacity: 0.7;
    transition: var(--transition-fast);
}

.video-item:hover .video-item-icon {
    opacity: 1;
    transform: scale(1.1);
}

.video-item-content {
    flex: 1;
    min-width: 0;
    overflow: hidden;
}

.video-item:hover {
    border-color: var(--primary-blue);
    background: rgba(0, 102, 255, 0.05);
}

.video-item.active {
    border-color: var(--primary-blue);
    background: rgba(0, 102, 255, 0.1);
}

.video-item-title {
    font-weight: 600;
    font-size: 0.875rem;
    margin-bottom: 0.2rem;
    color: var(--text-primary);
    line-height: 1.3;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.video-item-channel {
    font-size: 0.75rem;
    color: var(--text-muted);
}

.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl);
    text-align: center;
}

.empty-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    opacity: 0.5;
}

.empty-title {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.empty-text {
    color: var(--text-muted);
    font-size: 0.95rem;
}

/* ===== MAIN CONTENT ===== */
.main-content {
    flex: 1;
    padding: var(--spacing-lg);
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
    min-width: 0;
    overflow-x: hidden;
}

/* ===== WELCOME SCREEN ===== */
.welcome-screen {
    display: flex;
    align-items: center;
    width: 100%;
    max-width: 100%;
    justify-content: center;
    min-height: calc(100vh - 180px);
}

.welcome-content {
    text-align: center;
    max-width: 600px;
    width: 100%;
    padding: 0 var(--spacing-sm);
}

.welcome-title {
    font-family: var(--font-display);
    font-size: clamp(2.5rem, 6vw, 3.5rem);
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    display: inline-block;
}

.welcome-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.welcome-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.stat-box {
    padding: var(--spacing-md);
    background: var(--surface);
    border: 1px solid rgba(0, 102, 255, 0.2);
    border-radius: var(--radius-md);
    text-align: center;
}

.stat-box .stat-number {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-xs);
}

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

.feature-highlights {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.highlight-item {
    padding: var(--spacing-md);
    background: var(--surface);
    border: 1px solid rgba(0, 102, 255, 0.1);
    border-radius: var(--radius-md);
}

.highlight-icon {
    font-size: 2rem;
    margin-bottom: var(--spacing-xs);
}

.highlight-text {
    font-size: 0.95rem;
    font-weight: 500;
}

/* ===== VIDEO VIEWER ===== */
.video-viewer {
    animation: fadeIn 0.5s ease;
    width: 100%;
    max-width: 100%;
    overflow-x: hidden;
}

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

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

.video-header-card {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--surface);
    border: 1px solid rgba(0, 102, 255, 0.1);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(20px);
    transition: var(--transition-base);
}

.video-header-card:hover {
    border-color: rgba(0, 102, 255, 0.3);
    box-shadow: var(--shadow-md);
}

.video-thumbnail-container {
    position: relative;
    width: 280px;
    min-width: 280px;
    height: 157px;
    border-radius: var(--radius-md);
    overflow: hidden;
    cursor: pointer;
    transition: var(--transition-base);
}

.video-thumbnail-container:hover {
    transform: scale(1.02);
}

.video-thumbnail {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition-base);
    max-width: 100%;
}

.video-thumbnail-container:hover .video-thumbnail {
    filter: brightness(0.8);
}

.play-overlay {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60px;
    height: 60px;
    background: rgba(0, 102, 255, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    transition: var(--transition-base);
    cursor: pointer;
}

.video-thumbnail-container:hover .play-overlay {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1.1);
}

.duration-badge {
    position: absolute;
    bottom: var(--spacing-xs);
    right: var(--spacing-xs);
    padding: 0.25rem 0.5rem;
    background: rgba(0, 0, 0, 0.85);
    color: white;
    font-size: 0.75rem;
    font-weight: 600;
    border-radius: 4px;
    font-family: var(--font-mono);
}

.video-header-info {
    flex: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.video-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    line-height: 1.3;
    color: var(--text-primary);
}

.video-meta-row {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    color: var(--text-muted);
    font-size: 0.9rem;
}

.meta-item svg {
    opacity: 0.7;
}

/* ===== CONTENT SEARCH ===== */
.content-search {
    position: relative;
    margin-bottom: var(--spacing-lg);
}

.content-search .search-input {
    padding-right: 100px;
}

.search-results {
    position: absolute;
    right: var(--spacing-sm);
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* ===== CONTENT LAYOUT ===== */
.content-layout {
    display: grid;
    grid-template-columns: 250px 1fr;
    width: 100%;
    max-width: 100%;
    gap: var(--spacing-lg);
}

/* ===== TABLE OF CONTENTS ===== */
.toc-container {
    position: sticky;
    top: 100px;
    height: fit-content;
    background: var(--surface);
    border: 1px solid rgba(0, 102, 255, 0.08);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    max-height: calc(100vh - 200px);
    overflow-y: auto;
}

.toc-title {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.toc-list {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.toc-item {
    padding: 0.5rem var(--spacing-sm);
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 6px;
    font-size: 0.875rem;
    transition: var(--transition-base);
    cursor: pointer;
    border-left: 2px solid transparent;
}

.toc-item:hover {
    background: rgba(0, 102, 255, 0.08);
    color: var(--primary-blue);
    border-left-color: var(--primary-blue);
}

.toc-item.active {
    background: rgba(0, 102, 255, 0.12);
    color: var(--primary-blue);
    font-weight: 500;
    border-left-color: var(--primary-blue);
}

/* ===== CONTENT SECTIONS ===== */
.content-section {
    background: var(--surface);
    border: 1px solid rgba(0, 102, 255, 0.08);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    width: 100%;
    max-width: 100%;
    overflow-x: hidden;
    margin-bottom: var(--spacing-lg);
    transition: var(--transition-base);
}

.content-section:hover {
    border-color: rgba(0, 102, 255, 0.15);
}

.section-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.section-icon {
    font-size: 1.25rem;
    opacity: 0.8;
}

/* ===== TIMESTAMPS ===== */
.timestamps-list {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.timestamp-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: 0.75rem var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid rgba(0, 102, 255, 0.05);
    border-radius: var(--radius-sm);
    transition: var(--transition-base);
    cursor: pointer;
}

.timestamp-item:hover {
    border-color: var(--primary-blue);
    background: rgba(0, 102, 255, 0.08);
    transform: translateX(4px);
}

.timestamp-time {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--primary-blue);
    min-width: 65px;
    padding: 0.35rem 0.65rem;
    background: rgba(0, 102, 255, 0.12);
    border-radius: 6px;
    text-align: center;
    letter-spacing: 0.5px;
}

.timestamp-label {
    flex: 1;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.timestamp-item:hover .timestamp-label {
    color: var(--text-primary);
}

.timestamp-copy {
    opacity: 0;
    transition: var(--transition-base);
    width: 32px;
    height: 32px;
}

.timestamp-item:hover .timestamp-copy {
    opacity: 1;
}

/* ===== RESOURCES ===== */
.resources-grid {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.resource-category {
    margin-bottom: 0;
}

.category-title {
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-primary);
}

.resource-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: 0.75rem var(--spacing-md);
    background: var(--bg-tertiary);
    border: 1px solid rgba(0, 102, 255, 0.05);
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text-primary);
    transition: var(--transition-base);
    margin-bottom: 0.5rem;
}

.resource-link:hover {
    border-color: var(--primary-blue);
    background: rgba(0, 102, 255, 0.08);
    transform: translateX(4px);
}

.resource-icon {
    font-size: 1.25rem;
    opacity: 0.8;
}

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

.resource-title {
    font-weight: 500;
    margin-bottom: 0.25rem;
    font-size: 0.95rem;
}

.resource-url {
    font-size: 0.8rem;
    color: var(--text-muted);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ===== DESCRIPTION BODY ===== */
.description-body {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 0.95rem;
    width: 100%;
    max-width: 100%;
    overflow-wrap: break-word;
    word-wrap: break-word;
    word-break: break-word;
}

.description-body h1 {
    color: var(--text-primary);
    font-family: var(--font-display);
    font-size: 1.5rem;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.description-body h2 {
    color: var(--text-primary);
    font-family: var(--font-display);
    font-size: 1.25rem;
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.description-body h3 {
    color: var(--text-primary);
    font-family: var(--font-display);
    font-size: 1.1rem;
    margin-top: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
}

.description-body p {
    margin-bottom: var(--spacing-sm);
}

.description-body a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: var(--transition-base);
}

.description-body a:hover {
    color: var(--accent-cyan);
}

.description-body ul,
.description-body ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

.description-body code {
    background: rgba(0, 102, 255, 0.1);
    padding: 0.2rem 0.5rem;
    border-radius: 4px;
    font-family: var(--font-mono);
    font-size: 0.85em;
    color: var(--accent-cyan);
}

.description-body pre {
    background: var(--bg-tertiary);
    padding: var(--spacing-md);
    border-radius: var(--radius-sm);
    overflow-x: auto;
    margin: var(--spacing-sm) 0;
    max-width: 100%;
    border: 1px solid rgba(0, 102, 255, 0.1);
}

.description-body pre code {
    background: none;
    padding: 0;
}

.highlight {
    background: rgba(0, 212, 255, 0.25);
    padding: 0.1rem 0.3rem;
    border-radius: 3px;
    font-weight: 500;
}

/* ===== TAGS ===== */
.tags-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.tag {
    display: inline-flex;
    align-items: center;
    padding: 0.5rem var(--spacing-sm);
    background: var(--bg-tertiary);
    border: 1px solid rgba(0, 102, 255, 0.2);
    border-radius: 50px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: var(--transition-base);
    cursor: pointer;
}

.tag:hover {
    border-color: var(--primary-blue);
    background: rgba(0, 102, 255, 0.1);
    color: var(--primary-blue);
}

/* ===== MODAL ===== */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 2000;
    animation: modalFadeIn 0.3s ease;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

@keyframes modalFadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(5px);
}

.modal-content {
    position: relative;
    width: 90%;
    max-width: 600px;
    background: var(--bg-secondary);
    border: 1px solid rgba(0, 102, 255, 0.2);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    animation: modalSlideUp 0.3s ease;
}

@keyframes modalSlideUp {
    from {
        transform: translateY(50px);
        opacity: 0;
    }

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

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid rgba(0, 102, 255, 0.1);
}

.modal-title {
    font-family: var(--font-display);
    font-size: 1.5rem;
    font-weight: 600;
}

.modal-close {
    background: none;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: var(--spacing-xs);
    transition: var(--transition-base);
}

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

.modal-body {
    padding: var(--spacing-lg);
}

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 500;
    color: var(--text-primary);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: 0.75rem var(--spacing-sm);
    background: var(--bg-tertiary);
    border: 1px solid rgba(0, 102, 255, 0.2);
    border-radius: var(--radius-md);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 0.95rem;
    transition: var(--transition-base);
}

.form-textarea {
    resize: vertical;
    font-family: var(--font-mono);
    font-size: 0.85rem;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary-blue);
    box-shadow: 0 0 0 3px rgba(0, 102, 255, 0.1);
}

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

.modal-footer {
    display: flex;
    justify-content: flex-end;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    border-top: 1px solid rgba(0, 102, 255, 0.1);
}

/* ===== FOOTER ===== */
.app-footer {
    background: var(--bg-secondary);
    border-top: 1px solid rgba(0, 102, 255, 0.1);
    padding: var(--spacing-lg) 0;
    width: 100%;
    max-width: 100vw;
    overflow-x: hidden;
    text-align: center;
    margin-top: var(--spacing-2xl);
}

.app-footer .footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.app-footer p {
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
}

.app-footer a {
    color: var(--primary-blue);
    text-decoration: none;
    transition: var(--transition-base);
}

.app-footer a:hover {
    color: var(--accent-cyan);
}

.app-footer .footer-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
}

/* ===== RESPONSIVE DESIGN ===== */

/* Mobile Menu Toggle Button (hidden on desktop) */
.mobile-menu-toggle {
    display: none;
    position: fixed;
    bottom: 20px;
    right: 20px;
    width: 56px;
    height: 56px;
    background: var(--gradient-primary);
    border: none;
    border-radius: 50%;
    color: white;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    z-index: 1001;
    transition: var(--transition-base);
}

.mobile-menu-toggle:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-glow);
}

.mobile-menu-toggle svg {
    width: 24px;
    height: 24px;
}

/* Sidebar Overlay for Mobile */
.sidebar-overlay {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    backdrop-filter: blur(5px);
    z-index: 998;
    opacity: 0;
    transition: opacity var(--transition-base);
}

.sidebar-overlay.active {
    display: block;
    opacity: 1;
}

/* Tablet Landscape (1024px - 1200px) */
@media (max-width: 1200px) {
    .nav-container {
        padding: 0 var(--spacing-md);
    }

    .main-content {
        padding: var(--spacing-md);
    }

    .content-layout {
        grid-template-columns: 200px 1fr;
        gap: var(--spacing-md);
    }

    .toc-container {
        width: 200px;
    }
}

/* Tablet Portrait (768px - 1024px) */
@media (max-width: 1024px) {
    :root {
        --spacing-lg: 1.5rem;
        --spacing-xl: 2rem;
    }

    .content-layout {
        grid-template-columns: 1fr;
    }

    .toc-container {
        position: relative;
        top: 0;
        max-height: 300px;
        width: 100%;
        margin-bottom: var(--spacing-md);
    }

    .video-header-card {
        gap: var(--spacing-md);
    }

    .welcome-stats {
        gap: var(--spacing-sm);
    }

    .stat-box {
        padding: var(--spacing-sm);
    }

    .stat-box .stat-number {
        font-size: 1.75rem;
    }
}

/* Mobile Landscape & Small Tablets (480px - 768px) */
@media (max-width: 768px) {
    :root {
        --spacing-sm: 0.75rem;
        --spacing-md: 1rem;
        --spacing-lg: 1.25rem;
        --spacing-xl: 1.5rem;
    }

    /* Navigation adjustments */
    .nav {
        padding: var(--spacing-sm) 0;
    }

    .nav-container {
        padding: 0 var(--spacing-sm);
    }

    .logo-container {
        display: flex;
        align-items: center;
        gap: var(--spacing-xs);
    }

    .nav-logo {
        height: 32px;
    }

    .logo-text {
        font-size: 1.1rem;
    }

    .nav-actions {
        gap: var(--spacing-xs);
    }

    .btn {
        padding: 0.6rem 1rem;
        font-size: 0.875rem;
    }

    .btn span {
        display: none;
        /* Hide button text on mobile */
    }

    .btn svg {
        margin: 0;
    }

    /* Sidebar becomes overlay on mobile */
    .sidebar {
        position: fixed;
        left: -100%;
        top: 0;
        height: 100vh;
        z-index: 999;
        transition: left 0.3s ease;
        box-shadow: var(--shadow-lg);
        width: 280px;
        min-width: 280px;
    }

    .sidebar.active {
        left: 0;
    }

    /* Show mobile menu toggle */
    .mobile-menu-toggle {
        display: flex;
        align-items: center;
        justify-content: center;
    }

    /* Main container adjustments */
    .main-container {
        padding-top: 60px;
    }

    .main-content {
        padding: var(--spacing-sm);
    }

    /* Welcome screen */
    .welcome-screen {
        min-height: calc(100vh - 140px);
        padding: var(--spacing-md);
    }

    .welcome-title {
        font-size: clamp(1.75rem, 8vw, 2.5rem);
        margin-bottom: var(--spacing-sm);
    }

    .welcome-description {
        font-size: 1rem;
        margin-bottom: var(--spacing-md);
    }

    .welcome-stats {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
        margin-bottom: var(--spacing-md);
    }

    .stat-box {
        padding: var(--spacing-sm);
    }

    .stat-box .stat-number {
        font-size: 1.5rem;
    }

    .stat-box .stat-label {
        font-size: 0.85rem;
    }

    .feature-highlights {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
        margin-top: var(--spacing-md);
    }

    .highlight-item {
        padding: var(--spacing-sm);
    }

    .highlight-icon {
        font-size: 1.5rem;
    }

    /* Video header card */
    .video-header-card {
        flex-direction: column;
        padding: var(--spacing-md);
        gap: var(--spacing-md);
    }

    .video-thumbnail-container {
        width: 100%;
        min-width: 100%;
        height: auto;
        aspect-ratio: 16/9;
    }

    .video-title {
        font-size: 1.25rem;
    }

    .video-meta-row {
        gap: var(--spacing-sm);
        font-size: 0.85rem;
    }

    /* Content sections */
    .content-section {
        padding: var(--spacing-md);
        margin-bottom: var(--spacing-md);
    }

    .section-title {
        font-size: 1.1rem;
        margin-bottom: var(--spacing-sm);
    }

    /* Timestamps */
    .timestamp-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-xs);
        padding: var(--spacing-sm);
    }

    .timestamp-time {
        font-size: 0.85rem;
        min-width: auto;
    }

    .timestamp-label {
        font-size: 0.9rem;
    }

    .timestamp-copy {
        position: absolute;
        right: var(--spacing-sm);
        top: var(--spacing-sm);
        opacity: 1;
    }

    /* Resources */
    .resource-link {
        padding: var(--spacing-sm);
        gap: var(--spacing-xs);
    }

    .resource-icon {
        font-size: 1.1rem;
    }

    .resource-title {
        font-size: 0.9rem;
    }

    .resource-url {
        font-size: 0.75rem;
    }

    /* Search */
    .search-input {
        font-size: 0.9rem;
        padding: 0.65rem var(--spacing-sm) 0.65rem 2.5rem;
    }

    .content-search .search-input {
        padding-right: 80px;
    }

    /* Tags */
    .tag {
        font-size: 0.8rem;
        padding: 0.4rem 0.75rem;
    }

    /* Footer */
    .app-footer {
        padding: var(--spacing-md) 0;
        margin-top: var(--spacing-lg);
    }

    .footer-links {
        flex-direction: column;
        gap: var(--spacing-xs);
    }
}

/* Mobile Portrait (320px - 480px) */
@media (max-width: 480px) {
    :root {
        --spacing-xs: 0.375rem;
        --spacing-sm: 0.625rem;
        --spacing-md: 0.875rem;
        --spacing-lg: 1rem;
        --spacing-xl: 1.25rem;
    }

    /* Navigation */
    .nav-container {
        padding: 0 var(--spacing-xs);
    }

    .logo-text {
        font-size: 0.95rem;
    }

    .nav-logo {
        height: 28px;
    }

    .btn-icon {
        width: 36px;
        height: 36px;
    }

    /* Sidebar */
    .sidebar {
        width: 100%;
        min-width: 100%;
    }

    /* Main content */
    .main-content {
        padding: var(--spacing-xs);
    }

    /* Welcome screen */
    .welcome-title {
        font-size: clamp(1.5rem, 10vw, 2rem);
        line-height: 1.3;
    }

    .welcome-description {
        font-size: 0.9rem;
    }

    .stat-box .stat-number {
        font-size: 1.25rem;
    }

    .stat-box .stat-label {
        font-size: 0.8rem;
    }

    /* Video header */
    .video-header-card {
        padding: var(--spacing-sm);
    }

    .video-title {
        font-size: 1.1rem;
        line-height: 1.4;
    }

    .video-meta-row {
        font-size: 0.8rem;
    }

    .meta-item svg {
        width: 14px;
        height: 14px;
    }

    /* Content sections */
    .content-section {
        padding: var(--spacing-sm);
        margin-bottom: var(--spacing-sm);
        border-radius: var(--radius-sm);
    }

    .section-title {
        font-size: 1rem;
        gap: var(--spacing-xs);
    }

    .section-icon {
        font-size: 1.1rem;
    }

    /* Timestamps */
    .timestamp-item {
        padding: var(--spacing-xs);
        position: relative;
    }

    .timestamp-time {
        font-size: 0.8rem;
        padding: 0.3rem 0.5rem;
    }

    .timestamp-label {
        font-size: 0.85rem;
        padding-right: 40px;
        /* Space for copy button */
    }

    /* Resources */
    .category-title {
        font-size: 0.9rem;
        margin-bottom: 0.5rem;
    }

    .resource-link {
        padding: var(--spacing-xs);
    }

    .resource-title {
        font-size: 0.85rem;
    }

    /* Description */
    .description-body {
        font-size: 0.9rem;
        line-height: 1.6;
    }

    .description-body h1 {
        font-size: 1.25rem;
    }

    .description-body h2 {
        font-size: 1.1rem;
    }

    .description-body h3 {
        font-size: 1rem;
    }

    /* Table of contents */
    .toc-container {
        max-height: 250px;
    }

    .toc-title {
        font-size: 0.85rem;
    }

    .toc-item {
        font-size: 0.8rem;
        padding: 0.4rem var(--spacing-xs);
    }

    /* Search */
    .search-input {
        font-size: 0.85rem;
    }

    .search-icon {
        width: 18px;
        height: 18px;
    }

    /* Mobile menu toggle */
    .mobile-menu-toggle {
        width: 52px;
        height: 52px;
        bottom: 16px;
        right: 16px;
    }

    .mobile-menu-toggle svg {
        width: 22px;
        height: 22px;
    }
}

/* Touch device optimizations */
@media (hover: none) and (pointer: coarse) {

    /* Increase touch targets */
    .btn-icon {
        min-width: 44px;
        min-height: 44px;
    }

    .video-item {
        padding: 0.75rem;
        min-height: 60px;
    }

    .timestamp-item {
        min-height: 56px;
        padding: 0.75rem var(--spacing-md);
    }

    .resource-link {
        min-height: 56px;
        padding: 0.75rem var(--spacing-md);
    }

    .toc-item {
        min-height: 44px;
        padding: 0.65rem var(--spacing-sm);
    }

    /* Remove hover effects on touch devices */
    .btn:hover,
    .btn-icon:hover,
    .video-item:hover,
    .timestamp-item:hover,
    .resource-link:hover {
        transform: none;
    }

    /* Show copy buttons on touch devices */
    .timestamp-copy {
        opacity: 1;
    }
}

/* Landscape orientation on mobile */
@media (max-width: 768px) and (orientation: landscape) {
    .welcome-screen {
        min-height: auto;
        padding: var(--spacing-md) var(--spacing-sm);
    }

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

    .feature-highlights {
        grid-template-columns: repeat(3, 1fr);
    }

    .video-header-card {
        flex-direction: row;
    }

    .video-thumbnail-container {
        width: 40%;
        min-width: 40%;
    }
}

/* ===== SCROLLBAR ===== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: rgba(0, 102, 255, 0.3);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(0, 102, 255, 0.5);
}