/* ============================================
   RAG Tutorial - Modern CSS Stylesheet
   ============================================ */

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

:root {
    /* Color Palette */
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary-color: #8b5cf6;
    --accent-color: #06b6d4;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --border-color: #e5e7eb;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --info-color: #3b82f6;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-size-base: 16px;
    --line-height-base: 1.6;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Shadows */
    --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);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 300ms ease;
    --transition-slow: 500ms ease;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--text-primary);
    background-color: var(--bg-primary);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-sm) var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

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

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    transition: color var(--transition-fast);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width var(--transition-base);
}

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

.nav-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-primary);
    padding: var(--spacing-xs);
}

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

.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: calc(80px + var(--spacing-2xl)) var(--spacing-lg) var(--spacing-2xl);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg width="100" height="100" xmlns="http://www.w3.org/2000/svg"><defs><pattern id="grid" width="100" height="100" patternUnits="userSpaceOnUse"><path d="M 100 0 L 0 0 0 100" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.2;
    animation: fadeInUp 0.8s ease;
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: var(--spacing-md);
    opacity: 0.95;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-description {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xl);
    opacity: 0.9;
    line-height: 1.7;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.cta-button {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-xl);
    background: white;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    box-shadow: var(--shadow-lg);
    animation: fadeInUp 0.8s ease 0.6s both;
}

.cta-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl);
}

/* ============================================
   Main Content
   ============================================ */

.main-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-2xl) var(--spacing-lg);
}

.section {
    margin-bottom: var(--spacing-2xl);
    scroll-margin-top: 100px;
}

.section-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-md);
    border-bottom: 3px solid var(--primary-color);
}

.section-number {
    font-size: 3rem;
    font-weight: 700;
    color: var(--primary-color);
    opacity: 0.2;
    line-height: 1;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
}

/* ============================================
   Content Cards
   ============================================ */

.content-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
}

.content-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.card-title {
    font-size: 1.75rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--bg-tertiary);
}

.card-content {
    color: var(--text-secondary);
    line-height: var(--line-height-base);
}

.card-content p {
    margin-bottom: var(--spacing-md);
}

.card-content ul,
.card-content ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
}

.card-content li {
    margin-bottom: var(--spacing-xs);
    line-height: 1.7;
}

.card-content h4 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
}

/* ============================================
   Info Boxes
   ============================================ */

.info-box {
    background: var(--bg-secondary);
    border-left: 4px solid var(--info-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
}

.info-box.warning {
    border-left-color: var(--warning-color);
    background: #fffbeb;
}

.info-box h4 {
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    font-size: 1.125rem;
}

.info-box ul {
    margin-left: var(--spacing-md);
}

.info-box li {
    margin-bottom: var(--spacing-xs);
}

/* ============================================
   Flow Diagrams
   ============================================ */

.flow-diagram {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: var(--spacing-xl) 0;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.flow-diagram.vertical {
    flex-direction: column;
    align-items: center;
}

.flow-step {
    background: var(--bg-secondary);
    border: 2px solid var(--primary-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md);
    text-align: center;
    min-width: 150px;
    flex: 1;
    transition: all var(--transition-base);
}

.flow-step:hover {
    background: var(--primary-color);
    color: white;
    transform: scale(1.05);
}

.flow-step.vertical {
    width: 100%;
    max-width: 500px;
}

.flow-icon {
    width: 50px;
    height: 50px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.25rem;
    margin: 0 auto var(--spacing-sm);
}

.flow-step:hover .flow-icon {
    background: white;
    color: var(--primary-color);
}

.flow-step h4 {
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.flow-step:hover h4 {
    color: white;
}

.flow-step p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin: 0;
}

.flow-step:hover p {
    color: rgba(255, 255, 255, 0.9);
}

.flow-arrow {
    font-size: 2rem;
    color: var(--primary-color);
    font-weight: 700;
    flex-shrink: 0;
}

.flow-diagram.vertical .flow-arrow {
    transform: rotate(90deg);
    margin: var(--spacing-sm) 0;
}

/* ============================================
   Comparison Tables
   ============================================ */

.comparison-table {
    width: 100%;
    margin: var(--spacing-lg) 0;
    border-collapse: collapse;
    overflow-x: auto;
    display: block;
}

.comparison-row {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
}

.comparison-row.header {
    background: var(--primary-color);
    color: white;
    font-weight: 600;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
}

.comparison-row:last-child {
    border-bottom: none;
}

.comparison-row:not(.header):hover {
    background: var(--bg-secondary);
}

.comparison-cell {
    padding: var(--spacing-xs);
}

.comparison-cell strong {
    color: var(--primary-color);
    font-weight: 600;
}

/* ============================================
   Code Blocks
   ============================================ */

.code-block {
    background: #1e293b;
    border-radius: var(--radius-md);
    margin: var(--spacing-md) 0;
    overflow: hidden;
    box-shadow: var(--shadow-md);
}

.code-header {
    background: #0f172a;
    color: #cbd5e1;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 0.875rem;
    font-weight: 600;
    border-bottom: 1px solid #334155;
}

.code-block pre {
    margin: 0;
    padding: var(--spacing-md);
    overflow-x: auto;
}

.code-block code {
    font-family: 'Courier New', monospace;
    font-size: 0.875rem;
    line-height: 1.6;
    color: #e2e8f0;
    white-space: pre;
}

/* ============================================
   Source Grid
   ============================================ */

.source-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin: var(--spacing-lg) 0;
}

.source-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    transition: all var(--transition-base);
}

.source-item:hover {
    border-color: var(--primary-color);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.source-item h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.source-item ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.source-item li {
    padding: var(--spacing-xs) 0;
    padding-left: var(--spacing-md);
    position: relative;
    color: var(--text-secondary);
    font-size: 0.9375rem;
}

.source-item li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--primary-color);
    font-weight: 700;
}

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

.footer {
    background: var(--bg-tertiary);
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-xl) var(--spacing-lg);
    text-align: center;
    color: var(--text-secondary);
    margin-top: var(--spacing-2xl);
}

.footer-content p {
    margin-bottom: var(--spacing-xs);
}

/* ============================================
   Animations
   ============================================ */

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

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

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: white;
        width: 100%;
        text-align: center;
        transition: left var(--transition-base);
        box-shadow: var(--shadow-lg);
        padding: var(--spacing-lg) 0;
        gap: var(--spacing-md);
    }

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

    .nav-toggle {
        display: block;
    }

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

    .hero-subtitle {
        font-size: 1.25rem;
    }

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

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

    .flow-diagram {
        flex-direction: column;
    }

    .flow-arrow {
        transform: rotate(90deg);
        margin: var(--spacing-sm) 0;
    }

    .comparison-row {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }

    .comparison-row.header {
        display: none;
    }

    .comparison-cell::before {
        content: attr(data-label) ': ';
        font-weight: 600;
        color: var(--primary-color);
    }

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

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

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

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }

    .hero-subtitle {
        font-size: 1.125rem;
    }

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

    .card-title {
        font-size: 1.5rem;
    }
}

/* ============================================
   Smooth Scrolling
   ============================================ */

html {
    scroll-behavior: smooth;
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
    .navbar,
    .footer,
    .cta-button {
        display: none;
    }

    .hero {
        background: white;
        color: black;
        padding: var(--spacing-md);
    }

    .content-card {
        break-inside: avoid;
        page-break-inside: avoid;
    }
}