:root {
    /* Dark theme (default) */
    --color-primary: #0a0e27;
    --color-secondary: #1a1f3a;
    --color-accent: #00d4ff;
    --color-accent-2: #ff6b6b;
    --color-accent-3: #4ecdc4;
    --color-background: #0f0f23;
    --color-surface: #1a1a2e;
    --color-text: #ffffff;
    --color-text-muted: #a0a0a0;
    --color-border: #2a2a3e;
    
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-accent: linear-gradient(135deg, #00d4ff 0%, #4ecdc4 100%);
    --gradient-hero: linear-gradient(135deg, #0a0e27 0%, #1a1f3a 50%, #2a2f4a 100%);
    --gradient-card: linear-gradient(145deg, #1a1a2e 0%, #16213e 100%);
    
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-family-display: 'Space Grotesk', 'Inter', sans-serif;
    
    --max-width: 1200px;
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    --spacing-4xl: 6rem;
    
    --border-radius: 12px;
    --border-radius-lg: 20px;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.4);
}

/* Light theme */
[data-theme="light"] {
    --color-primary: #f8f9fa;
    --color-secondary: #e9ecef;
    --color-accent: #0066cc;
    --color-accent-2: #dc3545;
    --color-accent-3: #28a745;
    --color-background: #ffffff;
    --color-surface: #f8f9fa;
    --color-text: #212529;
    --color-text-muted: #6c757d;
    --color-border: #dee2e6;
    
    --gradient-primary: linear-gradient(135deg, #0066cc 0%, #0056b3 100%);
    --gradient-accent: linear-gradient(135deg, #0066cc 0%, #28a745 100%);
    --gradient-hero: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 50%, #dee2e6 100%);
    --gradient-card: linear-gradient(145deg, #ffffff 0%, #f8f9fa 100%);
    
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.15);
}

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Space+Grotesk:wght@400;500;600;700&display=swap');

* {
    box-sizing: border-box;
}

body {
    font-family: var(--font-family);
    line-height: 1.7;
    color: var(--color-text);
    background: var(--color-background);
    margin: 0;
    padding: 0;
    font-weight: 400;
    overflow-x: hidden;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(120, 119, 198, 0.3) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(255, 107, 107, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 40%, rgba(78, 205, 196, 0.1) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--spacing-xl);
}

/* Header */
.header {
    background: rgba(26, 26, 46, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-lg) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.site-title {
    font-family: var(--font-family-display);
    font-size: 1.75rem;
    font-weight: 700;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-decoration: none;
    margin: 0;
    transition: all 0.3s ease;
}

.site-title:hover {
    transform: scale(1.05);
}

/* Improved Navigation */
.nav {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
    justify-content: flex-end;
    align-items: center;
}

.nav a {
    color: var(--color-text-muted);
    text-decoration: none;
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
    font-size: 0.9rem;
    white-space: nowrap;
}

.nav a::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--gradient-accent);
    transition: left 0.3s ease;
    z-index: -1;
}

.nav a:hover {
    color: var(--color-text);
    transform: translateY(-2px);
}

.nav a:hover::before {
    left: 0;
}

/* Dropdown Menu */
.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-toggle {
    background: none;
    border: none;
    color: var(--color-text-muted);
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.dropdown-toggle:hover {
    color: var(--color-text);
    background: rgba(0, 212, 255, 0.1);
}

.dropdown-toggle svg {
    width: 12px;
    height: 12px;
    transition: transform 0.3s ease;
}

.dropdown-toggle.active svg {
    transform: rotate(180deg);
}

.dropdown-menu {
    position: absolute;
    top: 100%;
    right: 0;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-lg);
    min-width: 200px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all 0.3s ease;
    z-index: 1000;
    backdrop-filter: blur(20px);
}

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

.dropdown-menu a {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--color-text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    border-bottom: 1px solid var(--color-border);
}

.dropdown-menu a:last-child {
    border-bottom: none;
}

.dropdown-menu a:hover {
    background: rgba(0, 212, 255, 0.1);
    color: var(--color-text);
}

.dropdown-menu a.active {
    color: var(--color-accent);
    background: rgba(0, 212, 255, 0.1);
}

.nav a.active {
    color: var(--color-accent);
    background: rgba(0, 212, 255, 0.1);
    border: 1px solid rgba(0, 212, 255, 0.3);
}

/* Theme toggle button */
.theme-toggle {
    background: none;
    border: 1px solid var(--color-border);
    color: var(--color-text-muted);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    margin-left: var(--spacing-md);
}

.theme-toggle:hover {
    color: var(--color-accent);
    border-color: var(--color-accent);
    background: rgba(0, 212, 255, 0.1);
}

.theme-toggle svg {
    width: 16px;
    height: 16px;
    fill: currentColor;
}

/* Light theme specific adjustments */
[data-theme="light"] .theme-toggle {
    background: rgba(0, 102, 204, 0.1);
}

[data-theme="light"] .theme-toggle:hover {
    background: rgba(0, 102, 204, 0.2);
}

/* Main content */
.main {
    padding: var(--spacing-3xl) 0;
    min-height: calc(100vh - 200px);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-family-display);
    color: var(--color-text);
    font-weight: 700;
    line-height: 1.2;
    margin-top: var(--spacing-2xl);
    margin-bottom: var(--spacing-lg);
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
    margin-top: 0;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: clamp(1.75rem, 3vw, 2.5rem);
    position: relative;
    padding-bottom: var(--spacing-md);
}

h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: var(--gradient-accent);
    border-radius: 2px;
}

h3 {
    font-size: clamp(1.25rem, 2.5vw, 1.75rem);
    color: var(--color-accent);
}

h4 {
    font-size: 1.25rem;
}

p {
    margin-bottom: var(--spacing-lg);
    font-size: 1.1rem;
}

/* Links */
a {
    color: var(--color-accent);
    text-decoration: none;
    transition: all 0.3s ease;
}

a:hover {
    color: var(--color-accent-3);
    text-shadow: 0 0 10px rgba(0, 212, 255, 0.5);
}

/* Lists */
ul, ol {
    margin-bottom: var(--spacing-lg);
    padding-left: var(--spacing-xl);
}

li {
    margin-bottom: var(--spacing-sm);
    font-size: 1.05rem;
}

/* Tables */
table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--spacing-xl) 0;
    background: var(--gradient-card);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow);
}

th, td {
    padding: var(--spacing-lg);
    text-align: left;
    border-bottom: 1px solid var(--color-border);
}

th {
    background: var(--gradient-primary);
    color: var(--color-text);
    font-weight: 600;
    font-size: 1.1rem;
}

tr:nth-child(even) {
    background: rgba(255, 255, 255, 0.02);
}

tr:hover {
    background: rgba(0, 212, 255, 0.1);
    transform: scale(1.01);
    transition: all 0.3s ease;
}

/* Code */
code {
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
    background: rgba(0, 212, 255, 0.1);
    color: var(--color-accent);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 6px;
    font-size: 0.9em;
    border: 1px solid rgba(0, 212, 255, 0.2);
}

pre {
    background: var(--gradient-card);
    color: var(--color-text);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    overflow-x: auto;
    margin: var(--spacing-xl) 0;
    box-shadow: var(--shadow);
    border: 1px solid var(--color-border);
}

pre code {
    background: none;
    padding: 0;
    color: inherit;
    border: none;
}

/* Blockquotes */
blockquote {
    border-left: 4px solid var(--color-accent);
    padding: var(--spacing-lg) var(--spacing-xl);
    margin: var(--spacing-xl) 0;
    font-style: italic;
    color: var(--color-text-muted);
    background: var(--gradient-card);
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    box-shadow: var(--shadow);
    position: relative;
}

blockquote::before {
    content: '"';
    font-size: 4rem;
    color: var(--color-accent);
    position: absolute;
    top: -10px;
    left: var(--spacing-lg);
    font-family: serif;
}

/* Footer */
.footer {
    background: var(--gradient-card);
    color: var(--color-text);
    text-align: center;
    padding: var(--spacing-3xl) 0;
    margin-top: var(--spacing-4xl);
    border-top: 1px solid var(--color-border);
}

/* Hero section */
.hero {
    text-align: center;
    padding: var(--spacing-4xl) 0;
    background: var(--gradient-hero);
    border-radius: var(--border-radius-lg);
    margin-bottom: var(--spacing-3xl);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(circle at 30% 20%, rgba(0, 212, 255, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 70% 80%, rgba(255, 107, 107, 0.1) 0%, transparent 50%);
    pointer-events: none;
}

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

.hero h1 {
    margin-bottom: var(--spacing-lg);
    text-shadow: 0 0 30px rgba(0, 212, 255, 0.3);
}

.hero p {
    font-size: 1.25rem;
    color: var(--color-text-muted);
    max-width: 700px;
    margin: 0 auto var(--spacing-xl);
    line-height: 1.6;
}

/* Section links grid */
.section-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-3xl);
}

.section-link {
    background: var(--gradient-card);
    padding: var(--spacing-2xl);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow);
    text-decoration: none;
    color: inherit;
    transition: all 0.4s ease;
    position: relative;
    overflow: hidden;
    border: 1px solid var(--color-border);
}

.section-link::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--gradient-accent);
    opacity: 0.1;
    transition: left 0.4s ease;
    z-index: 0;
}

.section-link:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-accent);
}

.section-link:hover::before {
    left: 0;
}

.section-link-content {
    position: relative;
    z-index: 1;
}

.section-link h3 {
    margin-top: 0;
    margin-bottom: var(--spacing-md);
    font-size: 1.5rem;
    background: var(--gradient-accent);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-link p {
    margin: 0;
    color: var(--color-text-muted);
    font-size: 1rem;
    line-height: 1.6;
}

/* Methodology Section */
.methodology-section {
    margin: var(--spacing-3xl) 0;
    padding: var(--spacing-2xl);
    background: var(--gradient-card);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow);
}

.methodology-section h2 {
    margin-top: 0;
    margin-bottom: var(--spacing-xl);
    font-size: clamp(1.5rem, 3vw, 2rem);
}

.methodology-link {
    display: block;
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

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

.methodology-content {
    padding: var(--spacing-xl);
    background: var(--gradient-surface);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
    transition: all 0.3s ease;
}

.methodology-content:hover {
    border-color: var(--color-accent);
    background: rgba(0, 212, 255, 0.05);
}

.methodology-content h3 {
    color: var(--color-accent);
    margin-top: 0;
    margin-bottom: var(--spacing-md);
}

.methodology-content p {
    color: var(--color-text-muted);
    margin-bottom: 0;
}

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

.domains-section h2 {
    margin-bottom: var(--spacing-2xl);
    font-size: clamp(1.5rem, 3vw, 2rem);
}

.domain-links {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-xl);
    max-width: 1200px;
    margin: 0 auto;
}

.domain-link {
    display: block;
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
    animation: fadeInUp 0.6s ease forwards;
    opacity: 0;
    transform: translateY(20px);
}

.domain-link:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.domain-content {
    padding: var(--spacing-xl);
    background: var(--gradient-card);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.domain-content::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-accent);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.domain-link:hover .domain-content::before {
    transform: scaleX(1);
}

.domain-link:hover .domain-content {
    border-color: var(--color-accent);
    background: rgba(0, 212, 255, 0.05);
}

.domain-content h3 {
    color: var(--color-accent);
    margin-top: 0;
    margin-bottom: var(--spacing-md);
}

.domain-content p {
    color: var(--color-text-muted);
    margin-bottom: 0;
}

/* Animation delays for domain links */
.domain-link:nth-child(1) { animation-delay: 0.1s; }
.domain-link:nth-child(2) { animation-delay: 0.2s; }
.domain-link:nth-child(3) { animation-delay: 0.3s; }
.domain-link:nth-child(4) { animation-delay: 0.4s; }

/* Back link */
.back-link {
    display: inline-flex;
    align-items: center;
    margin-bottom: var(--spacing-xl);
    color: var(--color-accent);
    text-decoration: none;
    font-weight: 500;
    padding: var(--spacing-sm) var(--spacing-lg);
    background: rgba(0, 212, 255, 0.1);
    border-radius: var(--border-radius);
    border: 1px solid rgba(0, 212, 255, 0.2);
    transition: all 0.3s ease;
}

.back-link:hover {
    background: rgba(0, 212, 255, 0.2);
    transform: translateX(-5px);
}

.back-link::before {
    content: "←";
    margin-right: var(--spacing-sm);
    font-size: 1.2rem;
}

/* Responsive */
@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        gap: var(--spacing-md);
    }
    
    .nav {
        flex-wrap: wrap;
        justify-content: center;
        gap: var(--spacing-sm);
    }
    
    .nav a {
        font-size: 0.85rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .dropdown-toggle {
        font-size: 0.85rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
    
    .dropdown-menu {
        right: auto;
        left: 0;
        min-width: 180px;
    }
    
    .container {
        padding: 0 var(--spacing-lg);
    }
    
    .section-links {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .domain-links {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
        max-width: none;
    }
    
    .methodology-section {
        padding: var(--spacing-xl);
    }
    
    .hero {
        padding: var(--spacing-2xl) 0;
    }
}

@media (max-width: 480px) {
    .nav {
        flex-direction: column;
        align-items: center;
        gap: var(--spacing-xs);
    }
    
    .nav a {
        font-size: 0.8rem;
        padding: var(--spacing-xs) var(--spacing-sm);
    }
}

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

.section-link {
    animation: fadeInUp 0.6s ease forwards;
}

.section-link:nth-child(1) { animation-delay: 0.1s; }
.section-link:nth-child(2) { animation-delay: 0.2s; }
.section-link:nth-child(3) { animation-delay: 0.3s; }
.section-link:nth-child(4) { animation-delay: 0.4s; }
.section-link:nth-child(5) { animation-delay: 0.5s; }
.section-link:nth-child(6) { animation-delay: 0.6s; }
.section-link:nth-child(7) { animation-delay: 0.7s; }
.section-link:nth-child(8) { animation-delay: 0.8s; }