/* ===================================
   CTO Management - Main Stylesheet
   Medical Learning Platform
   =================================== */

/* CSS Variables for Theming */
:root {
    /* Light Mode Colors */
    --primary-color: #1e3a8a;
    --primary-light: #3b82f6;
    --primary-dark: #1e40af;
    --secondary-color: #dc2626;
    --secondary-light: #ef4444;
    --accent-color: #10b981;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #e2e8f0;
    --bg-card: #ffffff;
    
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-tertiary: #94a3b8;
    
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-primary: 'Inter', sans-serif;
    --font-heading: 'Poppins', sans-serif;
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
}

/* Dark Mode Colors */
body.dark-mode {
    --primary-color: #3b82f6;
    --primary-light: #60a5fa;
    --primary-dark: #2563eb;
    
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-card: #1e293b;
    
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-tertiary: #64748b;
    
    --border-color: #334155;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.6);
}

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

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

body {
    font-family: var(--font-primary);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color var(--transition-base), color var(--transition-base);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
}

h1 { font-size: 3rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 2rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1rem;
}

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

a:hover {
    color: var(--primary-light);
}

/* Container */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* Section */
.section {
    padding: var(--spacing-3xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-3xl);
}

.section-title {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.125rem;
    max-width: 700px;
    margin: 0 auto;
}

/* ===================================
   NAVIGATION
   =================================== */

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--bg-card);
    box-shadow: var(--shadow-md);
    z-index: 1000;
    transition: all var(--transition-base);
}

.navbar.scrolled {
    padding: 0.5rem 0;
    box-shadow: var(--shadow-lg);
}

.nav-container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 1rem var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-brand i {
    font-size: 1.75rem;
    color: var(--secondary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    transition: all var(--transition-fast);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary-color);
    background-color: var(--bg-secondary);
}

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

.theme-toggle,
.language-toggle {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: all var(--transition-fast);
}

.theme-toggle:hover,
.language-toggle:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-primary);
    cursor: pointer;
}

/* ===================================
   HERO SECTION
   =================================== */

.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding-top: 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, var(--primary-dark) 0%, var(--primary-color) 50%, var(--secondary-color) 100%);
    opacity: 0.05;
}

.hero-pattern {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        repeating-linear-gradient(45deg, transparent, transparent 35px, rgba(255,255,255,.05) 35px, rgba(255,255,255,.05) 70px);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
}

.hero-title {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.hero-title-main {
    font-size: 4rem;
    font-weight: 800;
    color: var(--primary-color);
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
}

.hero-title-sub {
    font-size: 2rem;
    font-weight: 400;
    color: var(--text-secondary);
    font-style: italic;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-lg);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-3xl);
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    max-width: 900px;
    margin: 0 auto;
}

.stat-item {
    padding: var(--spacing-lg);
    background: var(--bg-card);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.stat-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

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

/* ===================================
   BUTTONS
   =================================== */

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    border: none;
    border-radius: 0.5rem;
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
}

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

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

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    background: var(--bg-tertiary);
    transform: translateY(-2px);
}

.btn-outline {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
}

.btn-outline:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

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

/* ===================================
   TECHNIQUES SECTION
   =================================== */

.techniques-section {
    background: var(--bg-secondary);
}

.techniques-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-xl);
}

.technique-card {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    border: 2px solid transparent;
}

.technique-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
    border-color: var(--primary-color);
}

.technique-icon {
    width: 80px;
    height: 80px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    border-radius: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
    font-size: 2rem;
    color: white;
}

.technique-title {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    font-size: 1.5rem;
}

.technique-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.technique-btn {
    width: 100%;
    justify-content: center;
}

/* ===================================
   VISUALIZATIONS SECTION
   =================================== */

.visualizations-container {
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: var(--spacing-xl);
}

.visualization-main {
    background: var(--bg-card);
    border-radius: 1rem;
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-lg);
}

.threejs-canvas-wrapper {
    width: 100%;
    height: 600px;
    background: linear-gradient(135deg, #1e3a8a10 0%, #dc262610 100%);
    border-radius: 0.5rem;
    position: relative;
    overflow: hidden;
}

.loading-indicator {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    color: var(--text-secondary);
}

.loading-indicator i {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.visualization-controls {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
    flex-wrap: wrap;
}

.control-btn {
    flex: 1;
    min-width: 120px;
    padding: 0.75rem 1rem;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: all var(--transition-fast);
}

.control-btn:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

.control-btn i {
    font-size: 1.2rem;
}

.visualization-info {
    margin-top: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: 0.5rem;
    border-left: 4px solid var(--primary-color);
}

.visualization-info h4 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.visualization-info p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.visualization-sidebar {
    background: var(--bg-card);
    padding: var(--spacing-lg);
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.visualization-sidebar h3 {
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

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

.scenario-btn {
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    text-align: left;
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    transition: all var(--transition-fast);
}

.scenario-btn:hover,
.scenario-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    transform: translateX(5px);
}

.scenario-btn i {
    font-size: 1.5rem;
}

/* ===================================
   VIDEOS SECTION
   =================================== */

.video-filters {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
    justify-content: center;
}

.filter-btn {
    padding: 0.5rem 1.5rem;
    background: var(--bg-card);
    border: 2px solid var(--border-color);
    border-radius: 2rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    font-weight: 500;
}

.filter-btn:hover,
.filter-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.videos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: var(--spacing-xl);
}

.video-card {
    background: var(--bg-card);
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.video-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.video-thumbnail {
    position: relative;
    height: 200px;
    overflow: hidden;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform var(--transition-slow);
}

.video-card:hover .video-thumbnail img {
    transform: scale(1.1);
}

.video-thumbnail .fa-play-circle {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    font-size: 4rem;
    color: white;
    opacity: 0.9;
    transition: all var(--transition-base);
}

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

.video-duration {
    position: absolute;
    bottom: 10px;
    right: 10px;
    background: rgba(0, 0, 0, 0.8);
    color: white;
    padding: 0.25rem 0.5rem;
    border-radius: 0.25rem;
    font-size: 0.875rem;
}

.video-info {
    padding: var(--spacing-lg);
}

.video-info h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.video-meta {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    font-size: 0.875rem;
    color: var(--text-tertiary);
}

.video-meta span {
    display: flex;
    align-items: center;
    gap: 0.25rem;
}

.video-description {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-lg);
}

.video-play-btn {
    width: 100%;
    justify-content: center;
}

/* ===================================
   QUIZ SECTION
   =================================== */

.quiz-section {
    background: var(--bg-secondary);
}

.quiz-container {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--spacing-xl);
}

.quiz-sidebar {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.quiz-score-card {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    text-align: center;
}

.quiz-score-card h3 {
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.score-display {
    display: flex;
    align-items: baseline;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: var(--spacing-md);
}

.score-number {
    font-size: 4rem;
    font-weight: 700;
    color: var(--primary-color);
}

.score-total {
    font-size: 2rem;
    color: var(--text-secondary);
}

.score-percentage {
    font-size: 1.5rem;
    color: var(--accent-color);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.score-feedback {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.quiz-categories {
    background: var(--bg-card);
    padding: var(--spacing-lg);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
}

.quiz-categories h3 {
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

.category-btn {
    width: 100%;
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 0.5rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: all var(--transition-fast);
    text-align: left;
}

.category-btn:hover,
.category-btn.active {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
    transform: translateX(5px);
}

.quiz-actions {
    background: var(--bg-card);
    padding: var(--spacing-lg);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
}

.quiz-actions .btn {
    width: 100%;
    justify-content: center;
}

.quiz-main {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: 1rem;
    box-shadow: var(--shadow-lg);
}

.quiz-header {
    margin-bottom: var(--spacing-xl);
}

.progress-bar {
    height: 8px;
    background: var(--bg-secondary);
    border-radius: 1rem;
    overflow: hidden;
    margin-bottom: var(--spacing-md);
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--primary-light));
    border-radius: 1rem;
    transition: width var(--transition-base);
}

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

.quiz-question-card {
    margin-bottom: var(--spacing-xl);
}

.question-category-badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background: var(--primary-color);
    color: white;
    border-radius: 1rem;
    font-size: 0.875rem;
    margin-bottom: var(--spacing-lg);
}

.question-text {
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.6;
}

.question-answers {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.answer-option {
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: 0.75rem;
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.answer-option:hover {
    border-color: var(--primary-color);
    background: var(--bg-tertiary);
    transform: translateX(5px);
}

.answer-option.selected {
    background: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.answer-option.correct {
    background: var(--accent-color);
    color: white;
    border-color: var(--accent-color);
}

.answer-option.incorrect {
    background: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.answer-option-letter {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg-card);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.125rem;
}

.answer-option.selected .answer-option-letter,
.answer-option.correct .answer-option-letter,
.answer-option.incorrect .answer-option-letter {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

.quiz-navigation {
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-md);
}

.quiz-result {
    text-align: center;
    padding: var(--spacing-3xl) var(--spacing-lg);
}

.result-icon {
    font-size: 5rem;
    color: var(--accent-color);
    margin-bottom: var(--spacing-xl);
}

.result-title {
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
}

.result-score {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: var(--spacing-lg);
}

.result-message {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

/* ===================================
   GUIDELINES SECTION
   =================================== */

.guidelines-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-3xl);
}

.guideline-card {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    border-top: 4px solid var(--primary-color);
}

.guideline-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.guideline-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.guideline-logo {
    width: 80px;
    height: 80px;
    background: var(--primary-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-lg);
    font-size: 2rem;
    color: white;
}

.guideline-header h3 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.guideline-org {
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

.guideline-content h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.guideline-content ul {
    list-style: none;
    margin-bottom: var(--spacing-lg);
}

.guideline-content li {
    padding: var(--spacing-sm) 0;
    padding-left: var(--spacing-lg);
    position: relative;
    color: var(--text-secondary);
    line-height: 1.6;
}

.guideline-content li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-weight: 700;
}

.guideline-reference {
    padding: var(--spacing-md);
    background: var(--bg-secondary);
    border-radius: 0.5rem;
    margin-bottom: var(--spacing-lg);
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.guideline-btn {
    width: 100%;
    justify-content: center;
}

.additional-resources {
    background: var(--bg-card);
    padding: var(--spacing-xl);
    border-radius: 1rem;
    box-shadow: var(--shadow-md);
}

.additional-resources h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
}

.resources-list {
    display: grid;
    gap: var(--spacing-md);
}

.resource-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: 0.5rem;
    transition: all var(--transition-fast);
    color: var(--text-primary);
}

.resource-item:hover {
    background: var(--bg-tertiary);
    transform: translateX(5px);
}

.resource-item i:first-child {
    font-size: 1.5rem;
    color: var(--primary-color);
}

.resource-item i:last-child {
    margin-left: auto;
    color: var(--text-tertiary);
}

/* ===================================
   EXPERTS SECTION
   =================================== */

.experts-section {
    background: var(--bg-secondary);
}

.experts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-xl);
}

.expert-card {
    background: var(--bg-card);
    border-radius: 1rem;
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.expert-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.expert-image {
    position: relative;
    height: 250px;
    background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
    display: flex;
    align-items: center;
    justify-content: center;
}

.expert-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.expert-badge {
    position: absolute;
    top: 15px;
    right: 15px;
    width: 50px;
    height: 50px;
    background: var(--accent-color);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    box-shadow: var(--shadow-lg);
}

.expert-info {
    padding: var(--spacing-xl);
}

.expert-name {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.expert-title {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 0.25rem;
}

.expert-institution {
    color: var(--text-tertiary);
    font-size: 0.85rem;
    margin-bottom: var(--spacing-lg);
}

.expert-stats {
    display: flex;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    background: var(--bg-secondary);
    border-radius: 0.5rem;
}

.expert-stats .stat {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.expert-stats .stat i {
    color: var(--primary-color);
}

.expert-speciality {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.expert-social {
    display: flex;
    gap: var(--spacing-sm);
}

.social-link {
    width: 40px;
    height: 40px;
    background: var(--bg-secondary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.social-link:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-3px);
}

/* ===================================
   FOOTER
   =================================== */

.footer {
    background: var(--bg-card);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-3xl) 0 var(--spacing-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3,
.footer-section h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.footer-section p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.footer-tagline {
    font-style: italic;
    color: var(--primary-color);
    font-weight: 600;
}

.footer-links {
    list-style: none;
}

.footer-links li {
    margin-bottom: 0.5rem;
}

.footer-links a {
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

.footer-links a:hover {
    color: var(--primary-color);
}

.footer-social {
    display: flex;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.social-icon {
    width: 45px;
    height: 45px;
    background: var(--bg-secondary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    font-size: 1.2rem;
}

.social-icon:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-3px);
}

.footer-info a {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

/* ===================================
   MODAL
   =================================== */

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    padding: var(--spacing-lg);
    backdrop-filter: blur(5px);
}

.modal {
    background: var(--bg-card);
    border-radius: 1rem;
    max-width: 900px;
    max-height: 90vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
    animation: modalSlideIn var(--transition-base);
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

.modal-title {
    color: var(--text-primary);
    margin: 0;
}

.modal-close {
    background: none;
    border: none;
    font-size: 2rem;
    color: var(--text-secondary);
    cursor: pointer;
    transition: color var(--transition-fast);
}

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

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

.modal-section {
    margin-bottom: var(--spacing-xl);
}

.modal-section h3 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.modal-section p {
    color: var(--text-secondary);
    line-height: 1.8;
}

.modal-section ul {
    list-style: none;
    padding-left: 0;
}

.modal-section li {
    padding: var(--spacing-sm) 0;
    padding-left: var(--spacing-lg);
    position: relative;
    color: var(--text-secondary);
}

.modal-section li:before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 700;
}

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

@media (max-width: 1024px) {
    .visualizations-container,
    .quiz-container {
        grid-template-columns: 1fr;
    }
    
    .visualization-sidebar,
    .quiz-sidebar {
        order: -1;
    }
    
    .scenario-list,
    .quiz-categories {
        display: grid;
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
}

@media (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--bg-card);
        flex-direction: column;
        padding: var(--spacing-xl);
        transition: left var(--transition-base);
        box-shadow: var(--shadow-xl);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .hero-title-main {
        font-size: 2.5rem;
    }
    
    .hero-title-sub {
        font-size: 1.5rem;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
    }
    
    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .techniques-grid,
    .videos-grid,
    .experts-grid {
        grid-template-columns: 1fr;
    }
    
    .quiz-navigation {
        flex-direction: column;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .hero-stats {
        grid-template-columns: 1fr;
    }
    
    .video-filters {
        justify-content: flex-start;
    }
    
    .filter-btn {
        font-size: 0.875rem;
        padding: 0.4rem 1rem;
    }
}

/* ===================================
   UTILITY CLASSES
   =================================== */

.hidden {
    display: none !important;
}

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

.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mt-4 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mb-4 { margin-bottom: var(--spacing-xl); }

/* ===================================
   ANIMATIONS
   =================================== */

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.5s ease-in-out;
}

.slide-in-up {
    animation: slideInUp 0.6s ease-out;
}