/* ===== COMPLETE WEBSITE REDESIGN ===== */

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

/* Modern CSS Variables */
:root {
    /* Colors */
    --primary: #0f172a;
    --secondary: #1e293b;
    --accent: #3b82f6;
    --accent-light: #60a5fa;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    
    /* Text Colors */
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --text-light: #94a3b8;
    
    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --bg-dark: #0f172a;
    --bg-card: #ffffff;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #334155 100%);
    --gradient-accent: linear-gradient(135deg, #3b82f6 0%, #60a5fa 100%);
    --gradient-hero: linear-gradient(135deg, #0f172a 0%, #1e293b 25%, #334155 50%, #475569 75%, #64748b 100%);
    --gradient-card: linear-gradient(145deg, #ffffff 0%, #f8fafc 100%);
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);
    
    /* Border Colors */
    --border-color: #d1d5db;
    --border-color-hover: #3b82f6;
    --border-color-focus: #3b82f6;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-2xl: 2rem;
    --radius-full: 9999px;
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space: 0.75rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    
    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-serif: 'Playfair Display', Georgia, serif;
    --font-mono: 'JetBrains Mono', Consolas, monospace;
    
    /* Font Sizes */
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;
    --text-6xl: 3.75rem;
    --text-7xl: 4.5rem;
    
    /* Line Heights */
    --leading-tight: 1.25;
    --leading-snug: 1.375;
    --leading-normal: 1.5;
    --leading-relaxed: 1.625;
    --leading-loose: 2;
    
    /* Transitions */
    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Z-Index */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal: 1040;
    --z-popover: 1050;
    --z-tooltip: 1060;
}

/* Base Styles */
html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

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

.container-sm {
    max-width: 640px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

.container-lg {
    max-width: 1536px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 700;
    line-height: var(--leading-tight);
    color: var(--text-primary);
    margin-bottom: var(--space-md);
}

h1 {
    font-size: var(--text-6xl);
    font-weight: 800;
    color: var(--text-primary);
}

h2 {
    font-size: var(--text-4xl);
    font-weight: 700;
}

h3 {
    font-size: var(--text-2xl);
    font-weight: 600;
}

h4 {
    font-size: var(--text-xl);
    font-weight: 600;
}

h5 {
    font-size: var(--text-lg);
    font-weight: 600;
}

h6 {
    font-size: var(--text-base);
    font-weight: 600;
}

p {
    margin-bottom: var(--space-md);
    color: var(--text-secondary);
    line-height: var(--leading-relaxed);
}

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

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

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

li {
    margin-bottom: var(--space-xs);
    color: var(--text-secondary);
}

/* ===== HEADER & NAVIGATION ===== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: var(--z-sticky);
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.1);
    transition: var(--transition);
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--shadow-md);
}

.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-md) 0;
}

.nav-brand {
    font-family: var(--font-serif);
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
}

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: var(--space-xl);
}

.nav-item {
    position: relative;
}

.nav-link {
    color: var(--text-secondary);
    font-weight: 500;
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius);
    transition: var(--transition);
    position: relative;
}

.nav-link:hover {
    color: var(--accent);
    background: rgba(59, 130, 246, 0.1);
}

.nav-link.active {
    color: var(--accent);
    background: rgba(59, 130, 246, 0.1);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--accent);
    transition: var(--transition);
    transform: translateX(-50%);
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-sm);
}

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

/* ===== HERO SECTION ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: var(--gradient-hero);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="50" cy="50" r="0.5" fill="rgba(255,255,255,0.1)"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: white;
    max-width: 800px;
    margin: 0 auto;
}

.hero-title {
    font-size: var(--text-4xl);
    font-weight: 800;
    margin-bottom: var(--space-lg);
    color: #ffffff;
    line-height: var(--leading-tight);
}

.hero-subtitle {
    font-size: var(--text-2xl);
    font-weight: 300;
    margin-bottom: var(--space-xl);
    color: rgba(255, 255, 255, 0.9);
    line-height: var(--leading-relaxed);
}

.hero-description {
    font-size: var(--text-lg);
    margin-bottom: var(--space-2xl);
    color: rgba(255, 255, 255, 0.8);
    line-height: var(--leading-relaxed);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-buttons {
    display: flex;
    gap: var(--space-lg);
    justify-content: center;
    flex-wrap: wrap;
}

/* ===== BUTTONS ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    font-size: var(--text-base);
    font-weight: 600;
    text-decoration: none;
    border: none;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

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

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

.btn-secondary {
    background: rgba(255, 255, 255, 0.1);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.2);
    border-color: rgba(255, 255, 255, 0.5);
}

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

.btn-outline:hover {
    background: var(--accent);
    color: white;
}

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

.btn-ghost:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

/* ===== SECTIONS ===== */
.section {
    padding: var(--space-4xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--space-3xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.section-title {
    font-size: var(--text-4xl);
    font-weight: 700;
    margin-bottom: var(--space-md);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-subtitle {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    line-height: var(--leading-relaxed);
}

/* ===== CARDS ===== */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    border: 1px solid rgba(0, 0, 0, 0.05);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.card-header {
    margin-bottom: var(--space-lg);
}

.card-title {
    font-size: var(--text-xl);
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
}

.card-subtitle {
    font-size: var(--text-sm);
    color: var(--text-muted);
    font-weight: 500;
}

.card-body {
    margin-bottom: var(--space-lg);
}

.card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--space-lg);
    border-top: 1px solid rgba(0, 0, 0, 0.1);
}

/* ===== GRIDS ===== */
.grid {
    display: grid;
    gap: var(--space-xl);
}

.grid-2 {
    grid-template-columns: repeat(2, 1fr);
}

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

.grid-4 {
    grid-template-columns: repeat(4, 1fr);
}

/* ===== STATS ===== */
.stats {
    background: var(--bg-secondary);
    padding: var(--space-3xl) 0;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-xl);
}

.stat-item {
    text-align: center;
    padding: var(--space-xl);
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
}

.stat-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.stat-number {
    font-size: var(--text-4xl);
    font-weight: 800;
    color: var(--accent);
    margin-bottom: var(--space-sm);
    display: block;
}

.stat-label {
    font-size: var(--text-base);
    color: var(--text-secondary);
    font-weight: 500;
}

.stat-icon {
    width: 48px;
    height: 48px;
    margin: 0 auto var(--space-md);
    background: var(--gradient-accent);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: var(--text-xl);
}

/* ===== RESEARCH AREAS ===== */
.research-areas {
    padding: var(--space-4xl) 0;
    background: var(--bg-primary);
}

.research-chips {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-md);
    justify-content: center;
    margin-top: var(--space-xl);
}

.research-chip {
    display: inline-flex;
    align-items: center;
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-card);
    border: 2px solid var(--accent);
    border-radius: var(--radius-full);
    color: var(--accent);
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
}

.research-chip:hover {
    background: var(--accent);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ===== PUBLICATIONS ===== */
.publications {
    padding: var(--space-4xl) 0;
    background: var(--bg-secondary);
}

.publications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--space-xl);
    margin-top: var(--space-xl);
}

.publication-item {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    border-left: 4px solid var(--accent);
}

.publication-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
}

.publication-title {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--space-sm);
    color: var(--text-primary);
    line-height: var(--leading-snug);
}

.publication-authors {
    color: var(--text-secondary);
    font-size: var(--text-sm);
    margin-bottom: var(--space-md);
}

.publication-meta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.publication-year {
    background: var(--gradient-accent);
    color: white;
    padding: var(--space-xs) var(--space-md);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: 600;
}

.publication-citations {
    color: var(--text-muted);
    font-size: var(--text-sm);
    font-weight: 500;
}

.publication-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    color: var(--accent);
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
}

.publication-link:hover {
    color: var(--accent-light);
}

/* ===== FOOTER ===== */
.footer {
    background: var(--bg-dark);
    color: white;
    padding: var(--space-4xl) 0 var(--space-xl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-3xl);
    margin-bottom: var(--space-3xl);
}

.footer-section h3 {
    color: white;
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--space-lg);
}

.footer-section p,
.footer-section li {
    color: rgba(255, 255, 255, 0.8);
    line-height: var(--leading-relaxed);
}

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

.footer-section li {
    margin-bottom: var(--space-sm);
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: var(--transition);
}

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

.footer-bottom {
    text-align: center;
    padding-top: var(--space-xl);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

.social-links {
    display: flex;
    gap: var(--space-md);
    justify-content: center;
    margin-bottom: var(--space-lg);
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 48px;
    height: 48px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-lg);
    color: white;
    text-decoration: none;
    transition: var(--transition);
}

.social-link:hover {
    background: var(--accent);
    transform: translateY(-2px);
}

/* ===== RESPONSIVE DESIGN ===== */
@media (max-width: 1024px) {
    .container {
        padding: 0 var(--space-md);
    }
    
    .hero-title {
        font-size: var(--text-6xl);
    }
    
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-title {
        font-size: var(--text-5xl);
    }
    
    .hero-subtitle {
        font-size: var(--text-xl);
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .research-chips {
        justify-content: flex-start;
    }
    
    .publications-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: var(--space-xl);
        text-align: center;
    }
    
    .social-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-md);
    }
    
    .hero-title {
        font-size: var(--text-4xl);
    }
    
    .hero-subtitle {
        font-size: var(--text-lg);
    }
    
    .section-title {
        font-size: var(--text-3xl);
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .card {
        padding: var(--space-lg);
    }
    
    .btn {
        padding: var(--space-md) var(--space-lg);
        font-size: var(--text-sm);
    }
}

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

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

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

@keyframes pulse {
    0%, 100% {
        transform: scale(1);
    }
    50% {
        transform: scale(1.05);
    }
}

.animate-fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

.animate-fade-in-left {
    animation: fadeInLeft 0.6s ease-out;
}

.animate-fade-in-right {
    animation: fadeInRight 0.6s ease-out;
}

.animate-pulse {
    animation: pulse 2s infinite;
}

/* ===== UTILITY CLASSES ===== */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--space-xs); }
.mb-2 { margin-bottom: var(--space-sm); }
.mb-3 { margin-bottom: var(--space-md); }
.mb-4 { margin-bottom: var(--space-lg); }
.mb-5 { margin-bottom: var(--space-xl); }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: var(--space-xs); }
.mt-2 { margin-top: var(--space-sm); }
.mt-3 { margin-top: var(--space-md); }
.mt-4 { margin-top: var(--space-lg); }
.mt-5 { margin-top: var(--space-xl); }

.p-0 { padding: 0; }
.p-1 { padding: var(--space-xs); }
.p-2 { padding: var(--space-sm); }
.p-3 { padding: var(--space-md); }
.p-4 { padding: var(--space-lg); }
.p-5 { padding: var(--space-xl); }

.hidden { display: none; }
.block { display: block; }
.inline-block { display: inline-block; }
.flex { display: flex; }
.grid { display: grid; }

.items-center { align-items: center; }
.items-start { align-items: flex-start; }
.items-end { align-items: flex-end; }

.justify-center { justify-content: center; }
.justify-start { justify-content: flex-start; }
.justify-end { justify-content: flex-end; }
.justify-between { justify-content: space-between; }

.w-full { width: 100%; }
.h-full { height: 100%; }

.rounded { border-radius: var(--radius); }
.rounded-lg { border-radius: var(--radius-lg); }
.rounded-xl { border-radius: var(--radius-xl); }
.rounded-full { border-radius: var(--radius-full); }

.shadow { box-shadow: var(--shadow); }
.shadow-md { box-shadow: var(--shadow-md); }
.shadow-lg { box-shadow: var(--shadow-lg); }
.shadow-xl { box-shadow: var(--shadow-xl); }

/* ===== ACCESSIBILITY ===== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles */
*:focus {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
}

/* Skip link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 6px;
    background: var(--accent);
    color: white;
    padding: 8px;
    text-decoration: none;
    border-radius: var(--radius);
    z-index: var(--z-tooltip);
}

.skip-link:focus {
    top: 6px;
}