/* ================================
   CSS Variables & Design System
   ================================ */

:root {
    /* Colors - Refined Academic Palette */
    --color-primary: #1a365d;      /* Deep Navy */
    --color-accent: #c17d11;        /* Warm Gold */
    --color-text: #2d3748;          /* Charcoal */
    --color-text-light: #4a5568;    /* Medium Gray */
    --color-bg: #fafafa;             /* Warm White */
    --color-bg-secondary: #f7f7f7;   /* Light Gray */
    --color-border: #e2e8f0;         /* Subtle Border */
    
    /* Typography */
    --font-serif: 'Libre Baskerville', Georgia, serif;
    --font-sans: 'Work Sans', -apple-system, BlinkMacSystemFont, sans-serif;
    
    /* Spacing */
    --space-xs: 0.5rem;
    --space-sm: 1rem;
    --space-md: 2rem;
    --space-lg: 4rem;
    --space-xl: 6rem;
    
    /* Layout */
    --container-width: 1200px;
    --border-radius: 2px;
    
    /* Transitions */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ================================
   Reset & Base Styles
   ================================ */

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

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

body {
    font-family: var(--font-sans);
    font-weight: 400;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ================================
   Typography
   ================================ */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 700;
    line-height: 1.2;
    color: var(--color-primary);
    margin-bottom: var(--space-sm);
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); }
h2 { font-size: clamp(2rem, 4vw, 3rem); }
h3 { font-size: clamp(1.5rem, 3vw, 2rem); }
h4 { font-size: 1.25rem; }

p {
    margin-bottom: var(--space-sm);
}

.lead {
    font-size: 1.25rem;
    font-weight: 300;
    line-height: 1.8;
    color: var(--color-text-light);
}

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

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

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

/* ================================
   Layout Components
   ================================ */

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

section {
    padding: var(--space-xl) 0;
    position: relative;
}

.section-header {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.section-number {
    font-family: var(--font-serif);
    font-size: 1rem;
    font-weight: 700;
    color: var(--color-accent);
    opacity: 0.6;
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    margin: 0;
}

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

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

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

.nav-logo {
    font-family: var(--font-serif);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--color-primary);
}

.nav-links {
    display: flex;
    gap: var(--space-md);
}

.nav-links a {
    font-size: 0.95rem;
    font-weight: 500;
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--color-accent);
}

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

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    padding-top: var(--space-xl);
    background: linear-gradient(135deg, #fafafa 0%, #f0f0f0 100%);
    overflow: hidden;
}

.hero-content {
    max-width: 900px;
    padding: var(--space-md);
    text-align: center;
    position: relative;
    z-index: 2;
    animation: fadeInUp 1s ease-out;
}

.hero-label {
    font-size: 0.9rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.15em;
    color: var(--color-accent);
    margin-bottom: var(--space-sm);
    animation: fadeIn 1s ease-out 0.2s both;
}

.hero-title {
    font-size: clamp(3rem, 8vw, 5.5rem);
    line-height: 1.1;
    margin-bottom: var(--space-sm);
    animation: fadeInUp 1s ease-out 0.3s both;
}

.hero-accent {
    color: var(--color-accent);
    display: block;
}

.hero-subtitle {
    font-size: clamp(1.1rem, 2vw, 1.3rem);
    font-weight: 300;
    color: var(--color-text-light);
    line-height: 1.6;
    margin-bottom: var(--space-lg);
    animation: fadeIn 1s ease-out 0.5s both;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
    margin-top: var(--space-lg);
    animation: fadeInUp 1s ease-out 0.7s both;
}

.stat {
    text-align: center;
}

.stat-number {
    font-family: var(--font-serif);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
}

.stat-label {
    font-size: 0.85rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-light);
    margin-top: var(--space-xs);
}

.hero-decoration {
    position: absolute;
    top: 10%;
    right: -10%;
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(193, 125, 17, 0.08) 0%, transparent 70%);
    border-radius: 50%;
    z-index: 1;
}

/* ================================
   About Section
   ================================ */

.about {
    background: white;
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
    align-items: start;
}

.about-text p {
    margin-bottom: var(--space-md);
}

.about-highlights {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
}

.highlight-card {
    padding: var(--space-md);
    background: var(--color-bg-secondary);
    border-left: 3px solid var(--color-accent);
}

.highlight-card h3 {
    font-size: 1.1rem;
    margin-bottom: var(--space-sm);
    color: var(--color-primary);
}

.highlight-card ul {
    list-style: none;
}

.highlight-card li {
    padding: var(--space-xs) 0;
    color: var(--color-text-light);
    font-size: 0.95rem;
    line-height: 1.6;
}

.highlight-card li:before {
    content: "▹ ";
    color: var(--color-accent);
    margin-right: var(--space-xs);
}

/* ================================
   Research Section
   ================================ */

.research {
    background: var(--color-bg);
}

.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-md);
}

.research-card {
    padding: var(--space-md);
    background: white;
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.research-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(26, 54, 93, 0.1);
    border-color: var(--color-accent);
}

.research-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-sm);
}

.research-card h3 {
    font-size: 1.3rem;
    margin-bottom: var(--space-sm);
}

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

/* ================================
   Publications Section
   ================================ */

.publications {
    background: white;
}

.publication-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
}

.publication-item {
    padding: var(--space-md);
    border-left: 3px solid var(--color-border);
    transition: var(--transition);
}

.publication-item:hover {
    border-left-color: var(--color-accent);
    background: var(--color-bg-secondary);
}

.publication-item.featured {
    background: var(--color-bg-secondary);
    border-left-color: var(--color-accent);
    padding: var(--space-md);
}

.publication-type {
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-accent);
    margin-bottom: var(--space-xs);
}

.publication-title {
    font-size: 1.4rem;
    margin-bottom: var(--space-xs);
}

.publication-subtitle {
    font-size: 1.1rem;
    font-style: italic;
    color: var(--color-text-light);
    margin-bottom: var(--space-xs);
}

.publication-authors {
    font-size: 0.95rem;
    color: var(--color-text-light);
    margin-bottom: var(--space-xs);
}

.publication-meta {
    display: flex;
    gap: var(--space-md);
    font-size: 0.9rem;
    color: var(--color-text-light);
    margin-bottom: var(--space-sm);
}

.publication-abstract {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--color-text-light);
    margin: var(--space-sm) 0;
}

.publication-links {
    display: flex;
    gap: var(--space-sm);
    margin-top: var(--space-sm);
}

.btn-link {
    padding: 0.4rem 1rem;
    font-size: 0.85rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-primary);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

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

.view-all {
    text-align: center;
    margin-top: var(--space-lg);
}

.btn-primary {
    display: inline-block;
    padding: 0.8rem 2rem;
    font-size: 1rem;
    font-weight: 500;
    color: white;
    background: var(--color-primary);
    border: 2px solid var(--color-primary);
    transition: var(--transition);
}

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

/* ================================
   Profiles Section
   ================================ */

.profiles {
    background: var(--color-bg);
    padding: var(--space-lg) 0;
}

.profiles-title {
    text-align: center;
    margin-bottom: var(--space-lg);
}

.profiles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-md);
    max-width: 1000px;
    margin: 0 auto;
}

.profile-card {
    padding: var(--space-md);
    background: white;
    border: 1px solid var(--color-border);
    text-align: center;
    transition: var(--transition);
}

.profile-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(26, 54, 93, 0.1);
    border-color: var(--color-accent);
}

.profile-icon {
    font-size: 2.5rem;
    margin-bottom: var(--space-sm);
}

.profile-name {
    font-family: var(--font-serif);
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--space-xs);
}

.profile-id,
.profile-detail {
    font-size: 0.9rem;
    color: var(--color-text-light);
}

/* ================================
   Contact Section
   ================================ */

.contact {
    background: white;
}

.contact-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-lg);
}

.contact-info h3,
.contact-interests h3 {
    margin-bottom: var(--space-md);
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: var(--space-md);
    margin-top: var(--space-md);
}

.contact-item {
    font-size: 0.95rem;
    line-height: 1.6;
}

.contact-item strong {
    display: block;
    margin-bottom: var(--space-xs);
}

.contact-item a {
    color: var(--color-accent);
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.tag {
    padding: 0.5rem 1rem;
    font-size: 0.85rem;
    background: var(--color-bg-secondary);
    color: var(--color-text-light);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

.tag:hover {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

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

.footer {
    background: var(--color-primary);
    color: white;
    padding: var(--space-md) 0;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.9rem;
}

.footer-links {
    display: flex;
    gap: var(--space-md);
}

.footer-links a {
    color: white;
    opacity: 0.8;
    transition: var(--transition);
}

.footer-links a:hover {
    opacity: 1;
    color: var(--color-accent);
}

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

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

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

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

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: var(--space-md);
    }
    
    .about-grid,
    .contact-grid {
        grid-template-columns: 1fr;
    }
    
    .research-grid {
        grid-template-columns: 1fr;
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--space-sm);
    }
    
    .footer-content {
        flex-direction: column;
        gap: var(--space-sm);
        text-align: center;
    }
}

@media (max-width: 480px) {
    :root {
        --space-lg: 3rem;
        --space-xl: 4rem;
    }
    
    .publication-meta {
        flex-direction: column;
        gap: var(--space-xs);
    }
}