/* ===================================
   Global Styles & Variables
   =================================== */

:root {
    --primary-color: #4f46e5;
    --secondary-color: #10b981;
    --accent-color: #f59e0b;
    --bg-dark: #0f172a;
    --bg-darker: #020617;
    --bg-light: #1e293b;
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    --border-color: #334155;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --card-bg: #1e293b;
    --card-hover: #293548;
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
    --transition: all 0.3s ease;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

/* Scroll margin to account for fixed navbar */
section[id] {
    scroll-margin-top: 80px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    background-color: var(--bg-darker);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
    position: relative;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* ===================================
   Navigation Bar
   =================================== */

.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 9999;
    transition: var(--transition);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

.nav-logo i {
    font-size: 2rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    padding: 0.5rem 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: width 0.3s ease;
}

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

.nav-link:hover::after {
    width: 100%;
}

.nav-link.external {
    padding: 0.5rem 1rem;
    background: var(--gradient-primary);
    border-radius: 6px;
    color: white;
}

.nav-link.external::after {
    display: none;
}

.nav-link.external:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 3px;
    transition: var(--transition);
}

/* ===================================
   Hero Section
   =================================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    padding: 8rem 2rem 4rem;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    overflow: hidden;
    z-index: 1;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 20% 50%, rgba(79, 70, 229, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 80% 80%, rgba(16, 185, 129, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 900px;
}

.hero-title {
    font-size: 4.5rem;
    font-weight: 800;
    margin-bottom: 1rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: 2rem;
    color: var(--text-primary);
    margin-bottom: 1.5rem;
    font-weight: 600;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-description {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.hero-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease 0.6s both;
}

.btn {
    padding: 1rem 2.5rem;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 8px;
    text-decoration: none;
    transition: var(--transition);
    display: inline-block;
    cursor: pointer;
    border: none;
}

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

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    background: var(--primary-color);
    transform: translateY(-3px);
}

.scroll-indicator {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
}

.scroll-indicator i {
    font-size: 2rem;
    color: var(--text-muted);
}

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

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    40% {
        transform: translateX(-50%) translateY(-10px);
    }
    60% {
        transform: translateX(-50%) translateY(-5px);
    }
}

/* ===================================
   Section Styles
   =================================== */

.section {
    padding: 6rem 2rem;
    position: relative;
    background-color: var(--bg-darker);
    z-index: 2;
}

.section.alt-bg {
    background-color: var(--bg-dark);
    z-index: 2;
}

.section-title {
    font-size: 3rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ===================================
   Overview Section
   =================================== */

#overview {
    clear: both;
    margin-top: 0;
}

.overview-content {
    max-width: 1000px;
    margin: 0 auto;
}

.intro-text {
    font-size: 1.25rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    text-align: center;
}

.definition-card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 3rem;
    margin-bottom: 3rem;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--border-color);
}

.definition-icon {
    font-size: 4rem;
    text-align: center;
    margin-bottom: 1.5rem;
}

.definition-card h3 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.definition-card p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

.key-elements {
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.characteristics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.char-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.char-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.char-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.char-card h4 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

.why-matters {
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.1) 0%, rgba(16, 185, 129, 0.1) 100%);
    border-radius: 16px;
    padding: 2.5rem;
    border: 1px solid var(--border-color);
}

.why-matters h3 {
    font-size: 2rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.why-matters p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

/* ===================================
   Context Cards (Neural Networks & Agentic AI)
   =================================== */

.context-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.context-card {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 2.5rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.context-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.context-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.context-header i {
    font-size: 2.5rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.context-header h3 {
    font-size: 1.75rem;
    color: var(--text-primary);
}

.context-card p {
    font-size: 1.05rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.connection-points {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.tag {
    background: rgba(79, 70, 229, 0.2);
    color: var(--primary-color);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    border: 1px solid rgba(79, 70, 229, 0.3);
}

.learn-more {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
    transition: var(--transition);
}

.learn-more:hover {
    gap: 1rem;
    color: var(--secondary-color);
}

/* ===================================
   Fundamentals Section
   =================================== */

.concepts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.concept-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2.5rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

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

.concept-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.concept-card h3 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.concept-card p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.concept-card ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.concept-card li {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.5rem;
}

.complexity-spectrum {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 1.5rem;
    padding: 1.5rem;
    background: rgba(79, 70, 229, 0.05);
    border-radius: 8px;
    border: 1px solid rgba(79, 70, 229, 0.2);
}

.spectrum-item {
    flex: 1;
    text-align: center;
}

.spectrum-item .label {
    display: block;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 0.9rem;
}

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

.spectrum-arrow {
    font-size: 1.5rem;
    color: var(--primary-color);
    padding: 0 1rem;
}

.principles-section {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 3rem;
    border: 1px solid var(--border-color);
}

.principles-section h3 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
    text-align: center;
}

.principles-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.principle-item {
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
}

.principle-number {
    flex-shrink: 0;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    color: white;
}

.principle-content h4 {
    font-size: 1.3rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.principle-content p {
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ===================================
   Techniques Section
   =================================== */

.techniques-intro {
    text-align: center;
    max-width: 800px;
    margin: 0 auto 4rem;
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.technique-category {
    margin-bottom: 5rem;
}

.category-title {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 1rem;
}

.category-title i {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.category-desc {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 2rem;
}

.technique-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 2rem;
}

.technique-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.technique-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

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

.technique-header h4 {
    font-size: 1.5rem;
    color: var(--text-primary);
    flex: 1;
}

.technique-badge {
    background: var(--gradient-primary);
    color: white;
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
}

.technique-card > p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.technique-details {
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.technique-details p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.75rem;
}

.technique-details ul,
.technique-details ol {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.technique-details li {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.5rem;
}

.metrics-section {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 3rem;
    border: 1px solid var(--border-color);
    margin-top: 3rem;
}

.metrics-section h3 {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
    text-align: center;
}

.metrics-section > p {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    font-size: 1.1rem;
}

.metrics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.metric-card {
    background: rgba(79, 70, 229, 0.05);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid rgba(79, 70, 229, 0.2);
    transition: var(--transition);
}

.metric-card:hover {
    background: rgba(79, 70, 229, 0.1);
    border-color: var(--primary-color);
    transform: translateY(-3px);
}

.metric-card h4 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-size: 1.2rem;
}

.metric-card p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.95rem;
}

/* ===================================
   Applications Section
   =================================== */

.applications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 2.5rem;
}

.app-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2.5rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.app-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--secondary-color);
}

.app-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
}

.app-card h3 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.app-card > p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.app-details {
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.app-details p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.75rem;
}

.app-details ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.app-details li {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.5rem;
}

/* ===================================
   Challenges Section
   =================================== */

.challenges-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.challenge-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2.5rem;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.challenge-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--warning);
}

.challenge-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.challenge-card h3 {
    font-size: 1.75rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.challenge-card > p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1.5rem;
}

.challenge-details {
    padding-top: 1rem;
    border-top: 1px solid var(--border-color);
}

.challenge-details p {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.75rem;
}

.challenge-details ul {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

.challenge-details li {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.5rem;
}

.best-practices-section {
    background: var(--card-bg);
    border-radius: 16px;
    padding: 3rem;
    border: 1px solid var(--border-color);
}

.best-practices-section h3 {
    font-size: 2rem;
    margin-bottom: 2rem;
    color: var(--text-primary);
    text-align: center;
}

.practices-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.practice-card {
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
    background: rgba(16, 185, 129, 0.05);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid rgba(16, 185, 129, 0.2);
    transition: var(--transition);
}

.practice-card:hover {
    background: rgba(16, 185, 129, 0.1);
    border-color: var(--secondary-color);
    transform: translateY(-3px);
}

.practice-number {
    flex-shrink: 0;
    width: 40px;
    height: 40px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: 700;
    color: white;
}

.practice-content h4 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.practice-content p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.95rem;
}

/* ===================================
   Resources Section
   =================================== */

.resources-layout {
    display: flex;
    flex-direction: column;
    gap: 3rem;
}

.resource-category {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 2.5rem;
    border: 1px solid var(--border-color);
}

.resource-category h3 {
    font-size: 1.75rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.resource-category h3 i {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.resource-item {
    display: flex;
    gap: 1.5rem;
    align-items: flex-start;
    padding: 1.5rem;
    background: rgba(79, 70, 229, 0.05);
    border-radius: 8px;
    border: 1px solid rgba(79, 70, 229, 0.2);
    transition: var(--transition);
    text-decoration: none;
    color: inherit;
}

.resource-item:hover {
    background: rgba(79, 70, 229, 0.1);
    border-color: var(--primary-color);
    transform: translateX(5px);
}

.resource-item.external {
    border-color: rgba(16, 185, 129, 0.3);
    background: rgba(16, 185, 129, 0.05);
}

.resource-item.external:hover {
    background: rgba(16, 185, 129, 0.1);
    border-color: var(--secondary-color);
}

.resource-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.resource-content h4 {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.resource-content p {
    color: var(--text-secondary);
    line-height: 1.6;
    font-size: 0.95rem;
}

/* ===================================
   Footer
   =================================== */

.footer {
    background: var(--bg-darker);
    border-top: 1px solid var(--border-color);
    padding: 4rem 2rem 2rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-section h4 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

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

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: 0.75rem;
}

.footer-section a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-muted);
}

/* ===================================
   Responsive Design
   =================================== */

@media (max-width: 1024px) {
    .nav-menu {
        gap: 1.5rem;
    }

    .hero-title {
        font-size: 3.5rem;
    }

    .hero-subtitle {
        font-size: 1.75rem;
    }

    .technique-grid,
    .concepts-grid,
    .context-grid,
    .applications-grid,
    .challenges-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: var(--bg-dark);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        padding: 2rem;
        border-top: 1px solid var(--border-color);
        gap: 1rem;
    }

    .nav-menu.active {
        left: 0;
    }

    .hero {
        padding: 6rem 1rem 3rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-subtitle {
        font-size: 1.5rem;
    }

    .hero-description {
        font-size: 1.1rem;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .section {
        padding: 4rem 1rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .definition-card,
    .principles-section,
    .best-practices-section,
    .metrics-section {
        padding: 2rem;
    }

    .characteristics-grid,
    .metrics-grid,
    .practices-grid {
        grid-template-columns: 1fr;
    }

    .complexity-spectrum {
        flex-direction: column;
        gap: 1rem;
    }

    .spectrum-arrow {
        transform: rotate(90deg);
    }

    .category-title {
        font-size: 1.75rem;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1rem;
    }

    .nav-container {
        padding: 1rem;
    }

    .hero-title {
        font-size: 2rem;
    }

    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 1rem;
    }

    .char-card,
    .concept-card,
    .technique-card,
    .app-card,
    .challenge-card {
        padding: 1.5rem;
    }
}

/* ===================================
   Utility Classes
   =================================== */

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

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

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

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

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }