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

:root {
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --text-dark: #1f2937;
    --text-medium: #4b5563;
    --text-light: #6b7280;
    --border-color: #e5e7eb;
    --bg-light: #f9fafb;
    --white: #ffffff;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
}

html {
    font-size: 16px;
    line-height: 1.6;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text-dark);
    background-color: var(--white);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
    margin-bottom: var(--spacing-md);
    color: var(--text-dark);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-medium);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.2s ease;
}

a:hover {
    color: var(--primary-dark);
    text-decoration: underline;
}

/* ============================================
   Header
   ============================================ */
.site-header {
    background-color: var(--white);
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-xl) 0 var(--spacing-lg);
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    text-align: center;
}

.site-title a {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-dark);
    text-decoration: none;
}

.site-title a:hover {
    color: var(--primary-color);
    text-decoration: none;
}

.site-tagline {
    margin-top: var(--spacing-sm);
    font-size: 1.125rem;
    color: var(--text-light);
    font-weight: 400;
}

/* ============================================
   Navigation
   ============================================ */
.main-nav {
    background-color: var(--bg-light);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.nav-list {
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0;
}

.nav-list li a {
    display: block;
    padding: var(--spacing-sm) var(--spacing-md);
    color: var(--text-medium);
    font-weight: 500;
    text-decoration: none;
    transition: all 0.2s ease;
}

.nav-list li a:hover,
.nav-list li a.active {
    color: var(--primary-color);
    background-color: var(--white);
}

/* ============================================
   Main Content
   ============================================ */
.main-content {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-2xl) var(--spacing-md);
    width: 100%;
}

.page-container,
.post-container {
    max-width: 900px;
    margin: 0 auto;
}

.page-header,
.post-header {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 2px solid var(--border-color);
}

.subtitle {
    font-size: 1.25rem;
    color: var(--text-light);
    font-weight: 400;
}

.post-meta {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-top: var(--spacing-sm);
}

.post-footer {
    margin-top: var(--spacing-2xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.back-link {
    color: var(--primary-color);
    font-weight: 500;
}

/* ============================================
   Home Page Styles
   ============================================ */
.hero-section {
    text-align: center;
    padding: var(--spacing-2xl) 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--white);
    border-radius: 12px;
    margin-bottom: var(--spacing-2xl);
}

.hero-section h1 {
    color: var(--white);
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
}

.hero-section p {
    color: rgba(255, 255, 255, 0.95);
    font-size: 1.25rem;
    max-width: 800px;
    margin: 0 auto;
}

.home-section {
    margin-bottom: var(--spacing-2xl);
}

.home-section h2 {
    margin-bottom: var(--spacing-lg);
    color: var(--text-dark);
}

/* ============================================
   Research Areas
   ============================================ */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
}

.research-area {
    padding: var(--spacing-lg);
    background-color: var(--bg-light);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.research-area:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.research-area h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

/* ============================================
   People/Team Styles
   ============================================ */
.team-section {
    margin-bottom: var(--spacing-2xl);
}

.team-member {
    padding: var(--spacing-lg);
    background-color: var(--bg-light);
    border-radius: 8px;
    margin-bottom: var(--spacing-lg);
}

.team-member h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-xs);
}

.team-member .title {
    color: var(--text-light);
    font-style: italic;
    margin-bottom: var(--spacing-sm);
}

.students-list {
    list-style: none;
    padding-left: 0;
}

.students-list li {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--border-color);
}

.students-list li:last-child {
    border-bottom: none;
}

/* ============================================
   Publications
   ============================================ */
.publication-section {
    margin-bottom: var(--spacing-2xl);
}

.publication {
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    background-color: var(--bg-light);
    border-left: 3px solid var(--primary-color);
    border-radius: 4px;
}

.publication-title {
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: var(--spacing-xs);
    line-height: 1.4;
}

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

.publication-journal {
    color: var(--text-light);
    font-size: 0.9rem;
    font-style: italic;
}

.publication-meta {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xs);
    font-size: 0.875rem;
}

.publication-year {
    color: var(--primary-color);
    font-weight: 600;
}

.publication-citations {
    color: var(--text-light);
}

.year-group {
    margin-bottom: var(--spacing-xl);
}

.year-heading {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--border-color);
}

/* ============================================
   News List
   ============================================ */
.news-list {
    list-style: none;
}

.news-item {
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    background-color: var(--bg-light);
    border-radius: 8px;
    transition: transform 0.2s ease;
}

.news-item:hover {
    transform: translateX(4px);
}

.news-item h3 {
    margin-bottom: var(--spacing-sm);
}

.news-item h3 a {
    color: var(--text-dark);
}

.news-item h3 a:hover {
    color: var(--primary-color);
}

.news-date {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: var(--spacing-sm);
}

.news-excerpt {
    color: var(--text-medium);
}

/* ============================================
   Photos/Gallery
   ============================================ */
.photo-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.photo-item {
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.photo-item img {
    width: 100%;
    height: auto;
    display: block;
}

.coming-soon {
    text-align: center;
    padding: var(--spacing-2xl);
    background-color: var(--bg-light);
    border-radius: 8px;
    color: var(--text-light);
}

/* ============================================
   Contact Section
   ============================================ */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-lg);
}

.contact-section {
    padding: var(--spacing-lg);
    background-color: var(--bg-light);
    border-radius: 8px;
}

.contact-section h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.contact-section p {
    margin-bottom: var(--spacing-sm);
}

.join-us {
    margin-top: var(--spacing-xl);
    padding: var(--spacing-xl);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: var(--white);
    border-radius: 8px;
    text-align: center;
}

.join-us h3 {
    color: var(--white);
}

.join-us p {
    color: rgba(255, 255, 255, 0.95);
}

/* ============================================
   Footer
   ============================================ */
.site-footer {
    background-color: var(--text-dark);
    color: var(--white);
    margin-top: auto;
    padding: var(--spacing-xl) 0 var(--spacing-md);
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

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

.footer-section h3 {
    color: var(--white);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-sm);
}

.footer-section p {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.95rem;
}

.footer-section a {
    color: rgba(255, 255, 255, 0.9);
}

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

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

.footer-bottom p {
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.875rem;
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    html {
        font-size: 14px;
    }

    .site-title a {
        font-size: 2rem;
    }

    .hero-section h1 {
        font-size: 2rem;
    }

    .nav-list {
        flex-direction: column;
        align-items: stretch;
    }

    .nav-list li a {
        text-align: center;
    }

    .main-content {
        padding: var(--spacing-lg) var(--spacing-sm);
    }

    .research-grid,
    .contact-grid {
        grid-template-columns: 1fr;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }
}

@media (max-width: 480px) {
    .site-header {
        padding: var(--spacing-lg) 0 var(--spacing-sm);
    }

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

/* ============================================
   Utility Classes
   ============================================ */
.text-center {
    text-align: center;
}

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

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