:root {
    --primary: #1a56db;
    --primary-light: #e8effd;
    --primary-dark: #133ea0;
    --text: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --border: #e5e7eb;
    --border-light: #f3f4f6;
    --accent: #dc2626;
    --accent-light: #fef2f2;
    --tag-bg: #f0f4ff;
    --tag-text: #1a56db;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px 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);
    --radius: 10px;
    --max-width: 920px;
}

/* --- Dark theme overrides --- */
[data-theme="dark"] {
    --primary: #6b9fff;
    --primary-light: #1e2a4a;
    --primary-dark: #a3c4ff;
    --text: #e5e7eb;
    --text-secondary: #9ca3af;
    --text-light: #6b7280;
    --bg: #0f1117;
    --card-bg: #181a24;
    --border: #2a2d3a;
    --border-light: #1f2130;
    --tag-bg: #1e2a4a;
    --tag-text: #6b9fff;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
    --shadow: 0 1px 3px rgba(0,0,0,0.4), 0 1px 2px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.4), 0 2px 4px -1px rgba(0,0,0,0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.5), 0 4px 6px -2px rgba(0,0,0,0.3);
}
[data-theme="dark"] nav {
    background: rgba(15,17,23,0.85);
}
[data-theme="dark"] .hero-avatar img {
    border-color: var(--card-bg);
}
[data-theme="dark"] .hero-links a {
    background: var(--card-bg);
}
[data-theme="dark"] .timeline-item::before {
    border-color: var(--bg);
}
[data-theme="dark"] .timeline-item.edu::before {
    box-shadow: 0 0 0 2px #064e3b;
}
[data-theme="dark"] .section-icon.icon-award {
    background: #422006;
    color: #fbbf24;
}
[data-theme="dark"] .section-icon.icon-service {
    background: #1e1b4b;
    color: #818cf8;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 64px; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
}

::selection {
    background: var(--primary-light);
    color: var(--primary-dark);
}

/* --- Navigation --- */
nav {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}
nav .nav-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 56px;
}
nav .nav-name {
    font-weight: 700;
    font-size: 16px;
    color: var(--text);
    text-decoration: none;
}
nav .nav-links { display: flex; gap: 4px; }
nav .nav-links a {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 6px 12px;
    border-radius: 6px;
    transition: all 0.15s;
}
nav .nav-links a:hover,
nav .nav-links a.active {
    color: var(--primary);
    background: var(--primary-light);
}

/* --- Main Container --- */
.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* --- Hero / Profile Section --- */
.hero {
    padding: 48px 0 40px;
    display: flex;
    gap: 40px;
    align-items: flex-start;
}
.hero-avatar {
    flex-shrink: 0;
}
.hero-avatar img {
    width: 160px;
    height: 160px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid #fff;
    box-shadow: var(--shadow-md);
}
.hero-info { flex: 1; }
.hero-info h1 {
    font-family: 'Source Serif 4', Georgia, serif;
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 6px;
    color: var(--text);
    letter-spacing: -0.5px;
}
.hero-info .affiliation {
    font-size: 17px;
    color: var(--text-secondary);
    margin-bottom: 16px;
    font-weight: 400;
}
.hero-info .bio {
    font-size: 15px;
    color: var(--text);
    line-height: 1.75;
    margin-bottom: 20px;
}
.hero-links {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}
.hero-links a {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 7px 16px;
    font-size: 13px;
    font-weight: 500;
    text-decoration: none;
    border-radius: 8px;
    transition: all 0.15s;
    border: 1px solid var(--border);
    color: var(--text);
    background: #fff;
}
.hero-links a:hover {
    border-color: var(--primary);
    color: var(--primary);
    box-shadow: var(--shadow-sm);
}
.hero-links a svg {
    width: 16px;
    height: 16px;
}

/* --- Section --- */
.section {
    padding: 36px 0;
    border-top: 1px solid var(--border);
}
.section-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 24px;
}
.section-header h2 {
    font-family: 'Source Serif 4', Georgia, serif;
    font-size: 24px;
    font-weight: 700;
    color: var(--text);
}
.section-header .section-icon {
    width: 28px;
    height: 28px;
    background: var(--primary-light);
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    flex-shrink: 0;
}
.section-header .section-icon svg {
    width: 16px;
    height: 16px;
}
.section-header .section-icon.icon-award {
    background: #fef3c7;
    color: #d97706;
}
.section-header .section-icon.icon-service {
    background: #e0e7ff;
    color: #4338ca;
}

/* --- News --- */
.news-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}
.news-list li {
    display: flex;
    align-items: baseline;
    gap: 12px;
    font-size: 15px;
    padding: 8px 14px;
    border-radius: 8px;
    background: var(--card-bg);
    border: 1px solid var(--border-light);
}
.news-date {
    font-size: 13px;
    font-weight: 600;
    color: var(--primary);
    white-space: nowrap;
    min-width: 90px;
}
.news-text {
    color: var(--text);
}
.news-highlight {
    font-weight: 600;
}

/* --- Publications --- */
.pub-list {
    display: flex;
    flex-direction: column;
    gap: 16px;
}
.pub-card {
    display: flex;
    gap: 20px;
    padding: 18px;
    background: var(--card-bg);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
    transition: all 0.2s;
}
.pub-card:hover {
    border-color: var(--border);
    box-shadow: var(--shadow);
}
.pub-thumb {
    flex-shrink: 0;
    width: 200px;
    height: 120px;
    border-radius: 8px;
    overflow: hidden;
    background: var(--border-light);
}
.pub-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.pub-info { flex: 1; min-width: 0; }
.pub-info .pub-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 4px;
    line-height: 1.4;
}
.pub-info .pub-authors {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 4px;
    line-height: 1.5;
}
.pub-info .pub-authors strong {
    color: var(--text);
    font-weight: 600;
}
.pub-info .pub-venue {
    display: inline-block;
    font-size: 12px;
    font-weight: 600;
    color: var(--tag-text);
    background: var(--tag-bg);
    padding: 2px 10px;
    border-radius: 20px;
    margin-bottom: 8px;
}
.pub-info .pub-venue.preprint {
    color: var(--text-secondary);
    background: var(--border-light);
}
.pub-links {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}
.pub-links a {
    font-size: 12px;
    font-weight: 500;
    color: var(--primary);
    text-decoration: none;
    padding: 3px 10px;
    border: 1px solid var(--primary);
    border-radius: 5px;
    transition: all 0.15s;
}
.pub-links a:hover {
    background: var(--primary);
    color: #fff;
}

/* --- Experience Timeline --- */
.timeline {
    position: relative;
    padding-left: 28px;
}
.timeline::before {
    content: '';
    position: absolute;
    left: 7px;
    top: 6px;
    bottom: 6px;
    width: 2px;
    background: var(--border);
    border-radius: 1px;
}
.timeline-item {
    position: relative;
    padding-bottom: 24px;
}
.timeline-item:last-child { padding-bottom: 0; }
.timeline-item::before {
    content: '';
    position: absolute;
    left: -24px;
    top: 7px;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: var(--primary);
    border: 2px solid #fff;
    box-shadow: 0 0 0 2px var(--primary-light);
}
.timeline-item.edu::before {
    background: #059669;
    box-shadow: 0 0 0 2px #d1fae5;
}
.timeline-header {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 4px;
}
.timeline-org {
    font-size: 15px;
    font-weight: 600;
    color: var(--text);
}
.timeline-period {
    font-size: 13px;
    color: var(--text-light);
    font-weight: 500;
}
.timeline-role {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 2px;
}
.timeline-loc {
    font-size: 13px;
    color: var(--text-light);
}

/* --- Awards --- */
.awards-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 10px;
}
.awards-list li {
    font-size: 15px;
    padding: 12px 16px;
    background: var(--card-bg);
    border: 1px solid var(--border-light);
    border-radius: 8px;
    display: flex;
    align-items: flex-start;
    gap: 10px;
}
.awards-list li::before {
    content: '';
    display: inline-block;
    flex-shrink: 0;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--primary);
    margin-top: 9px;
}
.awards-list a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}
.awards-list a:hover { text-decoration: underline; }

/* --- Service / Talks --- */
.service-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 16px;
}
.service-card {
    padding: 18px 20px;
    background: var(--card-bg);
    border: 1px solid var(--border-light);
    border-radius: var(--radius);
}
.service-card h3 {
    font-size: 14px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 8px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}
.service-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}
.talks-list {
    list-style: none;
}
.talks-list li {
    font-size: 15px;
    padding: 12px 16px;
    background: var(--card-bg);
    border: 1px solid var(--border-light);
    border-radius: 8px;
}
.talks-list a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
}
.talks-list a:hover { text-decoration: underline; }

/* --- Footer --- */
footer {
    text-align: center;
    padding: 32px 0;
    color: var(--text-light);
    font-size: 13px;
    border-top: 1px solid var(--border);
    margin-top: 16px;
}
footer .globe-container {
    margin-bottom: 16px;
}

/* --- Responsive --- */
@media (max-width: 768px) {
    .hero {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 24px;
        padding: 32px 0;
    }
    .hero-avatar img {
        width: 130px;
        height: 130px;
    }
    .hero-links { justify-content: center; }
    .pub-card {
        flex-direction: column;
    }
    .pub-thumb {
        width: 100%;
        height: 180px;
    }
    .service-grid {
        grid-template-columns: 1fr;
    }
    nav .nav-links a {
        padding: 6px 8px;
        font-size: 12px;
    }
    .news-list li {
        flex-direction: column;
        gap: 2px;
    }
    .timeline-header {
        flex-direction: column;
    }
}

/* --- Fade-in animation --- */
.fade-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}
.fade-visible {
    opacity: 1;
    transform: translateY(0);
}

/* --- Theme toggle button --- */
.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 34px;
    height: 34px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--card-bg);
    cursor: pointer;
    color: var(--text-secondary);
    transition: all 0.15s;
    flex-shrink: 0;
    margin-left: 8px;
}
.theme-toggle:hover {
    color: var(--primary);
    border-color: var(--primary);
    background: var(--primary-light);
}
.theme-toggle svg {
    width: 18px;
    height: 18px;
}

/* --- Color transition for theme switch --- */
body, nav, .pub-card, .news-list li, .awards-list li,
.service-card, .talks-list li, .hero-links a, footer,
.section, .section-icon, .theme-toggle {
    transition: background-color 0.3s, color 0.3s, border-color 0.3s, box-shadow 0.3s;
}

@media print {
    nav { display: none; }
    body { background: #fff; }
    .pub-card:hover { box-shadow: none; }
    .theme-toggle { display: none; }
}