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

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
    scroll-behavior: smooth;
    overflow-x: hidden;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

h1, h2, h3, h4 {
    margin-bottom: 1rem;
    font-weight: 700;
}

a {
    color: var(--theme-primary, #1a365d);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: var(--theme-accent, #2563eb);
}

/* Header & Nav */
.main-header {
    background: #fff;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    display: flex;
    align-items: baseline;
    gap: 0.2rem;
}

.logo-highlight {
    color: var(--theme-primary, #1a365d);
}

.logo-sub {
    color: var(--theme-accent, #2563eb);
    font-weight: 300;
}

.main-nav ul {
    list-style: none;
    display: flex;
    gap: 2rem;
    overflow-x: auto;
    white-space: nowrap;
    scrollbar-width: thin;
    padding-bottom: 2px;
}

.main-nav a {
    font-weight: 600;
    font-size: 0.95rem;
    color: #4a5568;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.main-nav a:hover {
    color: var(--theme-primary, #1a365d);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--theme-primary);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--theme-primary, #1a365d) 0%, var(--theme-accent, #2563eb) 100%);
    color: #fff;
    padding: 8rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 3.5rem;
    margin-bottom: 1.5rem;
    font-weight: 800;
    letter-spacing: -1px;
}

.hero p {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    opacity: 0.9;
}

/* Sections */
section {
    padding: 5rem 0;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    color: var(--theme-primary, #1a365d);
    margin-bottom: 3rem;
    position: relative;
    padding-bottom: 1rem;
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: var(--theme-accent, #2563eb);
    border-radius: 2px;
}

/* Projects Grid */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.project-card {
    background: #fff;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 1px solid var(--theme-secondary, #e2e8f0);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

.project-image img {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.project-content {
    padding: 1.5rem;
}

.project-subtitle {
    font-size: 0.85rem;
    color: var(--theme-accent, #2563eb);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

/* Team Grid */
.team-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.team-member {
    background: #fff;
    padding: 2rem;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    border-top: 4px solid var(--theme-primary, #1a365d);
}

.team-photo {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    margin: 0 auto 1.5rem;
    background: var(--theme-secondary, #e2e8f0);
    overflow: hidden;
}

.team-photo img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.team-role {
    color: var(--theme-accent, #2563eb);
    font-weight: 600;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}

/* Publications Timeline Accordion */
.timeline-container {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.timeline-item {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    overflow: hidden;
    border: 1px solid var(--theme-secondary, #e2e8f0);
}

.timeline-header {
    width: 100%;
    padding: 1.5rem 2rem;
    background: #fff;
    border: none;
    display: flex;
    align-items: center;
    cursor: pointer;
    transition: background 0.3s;
    font-family: 'Inter', sans-serif;
    font-size: 1.1rem;
    text-align: left;
}

.timeline-header:hover {
    background: #f8f9fa;
}

.pub-year {
    font-weight: 800;
    color: var(--theme-primary, #1a365d);
    font-size: 1.4rem;
    margin-right: 1.5rem;
}

.pub-count {
    color: #6b7280;
    font-size: 0.95rem;
    flex-grow: 1;
}

.timeline-icon {
    color: var(--theme-primary);
    transition: transform 0.3s ease;
    font-size: 1.2rem;
}

.timeline-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease-out;
    background: #fafafa;
}

.publication-item {
    padding: 1.5rem 2rem 1.5rem 3.5rem;
    border-top: 1px solid var(--theme-secondary, #e2e8f0);
    position: relative;
    background: #fff;
}

.publication-item::before {
    content: '';
    position: absolute;
    left: 2rem;
    top: 2rem;
    bottom: -1.5rem;
    width: 2px;
    background: var(--theme-secondary, #e2e8f0);
}

.publication-item:last-child::before {
    display: none;
}

.publication-item::after {
    content: '';
    position: absolute;
    left: 1.7rem;
    top: 2rem;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    background: var(--theme-accent, #2563eb);
}

/* Footer */
.main-footer {
    background: #111827;
    color: #f9fafb;
    padding: 4rem 0 0;
}

.footer-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-info h3 {
    color: #fff;
    margin-bottom: 1rem;
}

.contact-text {
    opacity: 0.8;
}

.footer-logos {
    display: flex;
    gap: 1rem;
    align-items: center;
    justify-content: flex-end;
    flex-wrap: wrap;
}

.logo-box img {
    max-height: 60px;
    background: rgba(255,255,255,0.1);
    padding: 5px;
    border-radius: 4px;
}

.footer-bottom {
    text-align: center;
    padding: 1.5rem;
    background: #000;
    opacity: 0.8;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

/* Responsive */
@media (max-width: 768px) {
    .main-nav ul {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: #fff;
        padding: 1rem;
        box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    }
    .main-nav ul.active {
        display: flex;
    }
    .mobile-menu-toggle {
        display: block;
    }
    .hero h1 {
        font-size: 2.5rem;
    }
    .footer-container {
        grid-template-columns: 1fr;
    }
    .footer-logos {
        justify-content: flex-start;
    }
    .footer-bottom {
        flex-direction: column;
        gap: 1rem;
    }
}