/* Homepage theme. Used only by index.html; the notes and KB pages still use academic.css. */
:root {
    --primary-color: #1a365d;
    --secondary-color: #2b6cb0;
    --accent-color: #3182ce;
    --text-color: #2d3748;
    --light-gray: #f7fafc;
    --border-color: #e2e8f0;
    --dark-gray: #4a5568;
    --yellow-color: #ffcc00;
    --red-color: #ff2600;
    --green-color: #2f855a;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Avenir Next', 'Nunito Sans', -apple-system, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background: #fff;
}

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

a:hover {
    color: #4299e1;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 1.5rem 2rem 2rem;
}

/* ---------- Header ---------- */
header {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 2.5rem;
    align-items: center;
    padding-bottom: 1rem;
}

.profile-img {
    width: 170px;
    height: auto;
    border-radius: 8px;
    display: block;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15), 0 2px 6px rgba(0, 0, 0, 0.1);
}

.header-content h1 {
    font-size: 2.6rem;
    font-weight: 400;
    color: var(--primary-color);
    line-height: 1.2;
}

.name-en {
    font-family: 'Kaushan Script', cursive;
}

.title {
    display: block;
    font-size: 1.15rem;
    color: var(--dark-gray);
    font-weight: 500;
    margin: 0.2rem 0 0.9rem;
}

.title .uci {
    font-weight: 600;
    color: #0064a4;
}

.social-btn-row {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.social-btn-row a,
.interest-tag {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.88rem;
    font-weight: 500;
    color: var(--primary-color);
    padding: 0.32rem 0.8rem;
    border-radius: 20px;
    background: linear-gradient(135deg, #f5faff 0%, #eef5fd 100%);
    box-shadow: 0 3px 0 #ccdcec, 0 4px 8px rgba(0, 0, 0, 0.06);
    transition: background 0.2s ease, color 0.2s ease, box-shadow 0.1s ease, transform 0.1s ease;
}

.social-btn-row a:hover,
.interest-tag:hover {
    background: linear-gradient(135deg, #1a365d 0%, #2b6cb0 60%, #4299e1 100%);
    color: #fff;
    box-shadow: 0 3px 0 #1a365d, 0 4px 8px rgba(0, 0, 0, 0.15);
}

.social-btn-row a:active {
    transform: translateY(2px);
    box-shadow: 0 1px 0 #c5d3e0, 0 2px 4px rgba(0, 0, 0, 0.1);
}

.social-btn-row i {
    font-size: 0.95rem;
}

.email-copy-btn {
    position: relative;
}

.email-tooltip {
    opacity: 0;
    visibility: hidden;
    position: absolute;
    bottom: calc(100% + 4px);
    right: 0;
    font-size: 0.65rem;
    color: var(--dark-gray);
    background: rgba(255, 255, 255, 0.9);
    padding: 1px 6px;
    border-radius: 99px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
    white-space: nowrap;
    pointer-events: none;
    transition: opacity 0.15s ease;
}

.email-copy-btn:hover .email-tooltip {
    opacity: 1;
    visibility: visible;
}

/* ---------- Sticky nav ---------- */
nav {
    background: #fff;
    padding: 0.7rem 1.5rem;
    margin: 0 -1rem 2rem;
    border-radius: 0 0 12px 12px;
    border: 2px solid var(--secondary-color);
    border-top: none;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 4px 16px rgba(26, 54, 93, 0.1), 0 2px 6px rgba(26, 54, 93, 0.08);
}

nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.15rem;
}

nav a {
    color: var(--secondary-color);
    font-weight: 500;
    padding: 0.4rem 0.7rem;
    border-radius: 6px;
    display: inline-block;
    transition: background 0.2s ease, color 0.2s ease;
}

nav a:hover,
nav a.active {
    background: #e6f1fb;
    color: var(--primary-color);
}

/* ---------- Sections ---------- */
section {
    margin-bottom: 2.5rem;
    scroll-margin-top: 80px;
}

h2 {
    font-size: 1.75rem;
    color: var(--primary-color);
    margin-bottom: 1.2rem;
    font-weight: 600;
}

h2::after {
    content: '';
    display: block;
    width: 36px;
    height: 3px;
    background: linear-gradient(90deg, #1a365d, #4299e1);
    border-radius: 2px;
    margin-top: 2px;
}

h2 .h2-note {
    font-size: 0.9rem;
    font-weight: 400;
    color: var(--dark-gray);
}

h3.sub-heading {
    color: var(--secondary-color);
    font-size: 1.25rem;
    margin: 1.6rem 0 0.9rem;
}

/* ---------- About ---------- */
.about-text {
    font-size: 0.98rem;
    line-height: 1.6;
    margin-bottom: 0.7rem;
    text-align: justify;
}

.topics-heading {
    font-weight: 600;
    color: var(--primary-color);
    margin-top: 0.4rem;
}

.topics-heading span {
    background: linear-gradient(transparent 60%, #ffe98a 60%);
}

.topic-list {
    list-style: none;
    margin: 0.55rem 0 0;
    padding-left: 1.5rem;
}

.topic-list li {
    display: flex;
    gap: 14px;
    align-items: flex-start;
    padding: 2px 0;
    font-size: 0.93rem;
}

.topic-list li::before {
    content: '';
    flex-shrink: 0;
    width: 6px;
    height: 6px;
    border: 2px solid var(--secondary-color);
    border-radius: 50%;
    margin-top: 7px;
}

.topic-hl {
    background: linear-gradient(transparent 60%, #e4eefb 60%);
    font-weight: 600;
    color: var(--primary-color);
}

.research-interests {
    display: flex;
    flex-wrap: wrap;
    gap: 0.8rem;
    margin-top: 1.2rem;
}

.interest-tag {
    cursor: default;
}

/* ---------- News ---------- */
.news-timeline {
    position: relative;
    margin-left: 6px;
    padding-left: 1.4rem;
}

.news-timeline::before {
    content: '';
    position: absolute;
    left: 4px;
    top: 0.4rem;
    bottom: 0.2rem;
    width: 2px;
    background: linear-gradient(180deg, var(--secondary-color), var(--border-color));
}

.news-item {
    position: relative;
    margin-bottom: 0.9em;
    font-size: 0.93rem;
    color: var(--primary-color);
}

.news-item::before {
    content: '';
    position: absolute;
    left: -1.4rem;
    top: 0.45rem;
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: #fff;
    border: 2px solid var(--secondary-color);
    transform: translateX(-1px);
}

.news-item.upcoming::before {
    border-color: var(--yellow-color);
    background: var(--yellow-color);
}

.news-date {
    font-weight: 700;
}

.news-item.upcoming .news-date {
    color: #8a6a00;
}

.badge {
    display: inline-block;
    vertical-align: middle;
    margin: 0 0.3rem;
    font-weight: 700;
    font-size: 0.62rem;
    letter-spacing: 0.04em;
    line-height: 1.4;
    padding: 2px 8px 1px;
    color: #fff;
    text-transform: uppercase;
    clip-path: polygon(7px 0, 100% 0, 100% 100%, 0 100%, 0 7px);
}

.badge.upcoming {
    background: linear-gradient(135deg, #ffe066 0%, #ffcc00 55%, #f2b400 100%);
    color: #5b4500;
}

.badge.accepted {
    background: linear-gradient(135deg, #ff5a3c 0%, #ff2600 55%, #db1f00 100%);
}

.badge.review {
    background: linear-gradient(135deg, #4299e1 0%, #2b6cb0 100%);
}

/* ---------- Publications / project cards ---------- */
.year-section {
    margin-bottom: 1.4rem;
}

.year-header {
    font-size: 1.2rem;
    color: #8a6a00;
    margin-bottom: 0.6rem;
    font-weight: 700;
    padding-left: 1rem;
    position: relative;
}

.year-header::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 10px;
    border-radius: 3px;
    background: linear-gradient(180deg, #ffe066 0%, #ffcc00 55%, #f2b400 100%);
}

.publication {
    background: #fff;
    padding: 0.85rem 1rem;
    margin-bottom: 0.7rem;
    border: 1px solid #eef1f5;
    border-radius: 8px;
    box-shadow: 0 1px 4px rgba(26, 54, 93, 0.05);
    transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.publication:hover {
    box-shadow: 0 4px 12px rgba(26, 54, 93, 0.08);
    transform: translateY(-2px);
}

.publication-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--primary-color);
    line-height: 1.35;
    margin-bottom: 0.25rem;
}

.publication-meta {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 0.3rem 0.8rem;
    font-size: 0.9rem;
    margin-bottom: 0.35rem;
}

.publication-authors {
    color: var(--dark-gray);
    flex: 1;
    min-width: 200px;
}

.publication-authors strong {
    color: var(--text-color);
}

.publication-venue {
    color: var(--secondary-color);
    font-weight: 600;
}

.publication-summary {
    font-size: 0.88rem;
    color: var(--dark-gray);
    margin-bottom: 0.4rem;
    text-align: justify;
}

.publication-links {
    display: flex;
    gap: 0.4rem;
    flex-wrap: wrap;
}

.publication-links a {
    color: var(--accent-color);
    padding: 0.1rem 0.5rem;
    border: 1px solid var(--accent-color);
    border-radius: 3px;
    font-size: 0.8rem;
    transition: all 0.25s ease;
}

.publication-links a:hover {
    background: var(--accent-color);
    color: #fff;
}

.project-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0.7rem;
}

.project-grid .publication {
    margin-bottom: 0;
    display: flex;
    flex-direction: column;
}

.project-grid .publication-summary {
    flex: 1;
}

.project-grid .publication:last-child:nth-child(odd) {
    grid-column: 1 / -1;
}

.project-tag {
    font-size: 0.78rem;
    color: var(--dark-gray);
    font-weight: 500;
    margin-bottom: 0.25rem;
}

/* ---------- Experience timeline ---------- */
.exp-item {
    margin-bottom: 1.3rem;
    padding-left: 1rem;
    border-left: 2px solid var(--border-color);
    transition: border-color 0.2s ease;
}

.exp-item:hover {
    border-left-color: var(--secondary-color);
}

.exp-item h4 {
    color: var(--primary-color);
    font-size: 1rem;
}

.exp-item .institution {
    color: var(--secondary-color);
    font-weight: 500;
    font-size: 0.92rem;
}

.exp-item .year {
    color: var(--dark-gray);
    font-size: 0.88rem;
}

.exp-item p {
    font-size: 0.9rem;
    margin-top: 0.2rem;
}

/* ---------- Simple lists (coursework, awards, resources) ---------- */
.dot-list {
    list-style: none;
    padding-left: 0.3rem;
}

.dot-list li {
    display: flex;
    gap: 12px;
    align-items: flex-start;
    font-size: 0.93rem;
    padding: 3px 0;
}

.dot-list li::before {
    content: '';
    flex-shrink: 0;
    width: 6px;
    height: 6px;
    border: 2px solid var(--secondary-color);
    border-radius: 50%;
    margin-top: 8px;
}

.dot-list strong {
    color: var(--primary-color);
}

.two-col {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0 2rem;
}

details.more summary {
    cursor: pointer;
    color: var(--secondary-color);
    font-weight: 500;
    font-size: 0.92rem;
    margin-top: 0.4rem;
}

/* ---------- Contact / footer ---------- */
.contact-grid {
    display: grid;
    grid-template-columns: 1fr 320px;
    gap: 1.5rem;
    align-items: start;
}

.contact-grid iframe {
    width: 100%;
    height: 190px;
    border: 0;
    border-radius: 8px;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.12);
}

footer {
    text-align: center;
    font-size: 0.82rem;
    color: var(--dark-gray);
    border-top: 1px solid var(--border-color);
    padding: 1.2rem 0 0.5rem;
}

/* ---------- Accessibility ---------- */
a:focus-visible,
.interest-tag:focus-visible {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
    border-radius: 4px;
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        transition: none !important;
    }

    .publication:hover {
        transform: none;
    }
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
    .container {
        padding: 1rem 16px;
    }

    header {
        grid-template-columns: 1fr;
        gap: 1rem;
        justify-items: center;
        text-align: center;
    }

    .profile-img {
        width: 140px;
    }

    .header-content h1 {
        font-size: 2rem;
    }

    .social-btn-row {
        justify-content: center;
    }

    nav {
        margin: 0 -16px 1.5rem;
        padding: 0.5rem 0.5rem;
        border-radius: 0;
        border-left: none;
        border-right: none;
    }

    nav ul {
        flex-wrap: nowrap;
        justify-content: flex-start;
        overflow-x: auto;
        scrollbar-width: none;
    }

    nav ul::-webkit-scrollbar {
        display: none;
    }

    nav a {
        white-space: nowrap;
        font-size: 0.92rem;
    }

    .about-text,
    .publication-summary {
        text-align: left;
    }

    .topic-list {
        padding-left: 0.3rem;
    }

    .project-grid,
    .two-col,
    .contact-grid {
        grid-template-columns: 1fr;
    }
}