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

:root {
    --primary: #16305c;
    --primary-light: #2c5282;
    --accent: #2563eb;
    --accent-soft: rgba(37, 99, 235, 0.07);
    --amber: #b45309;
    --amber-soft: rgba(217, 119, 6, 0.09);
    --text: #1f2937;
    --text-light: #4b5563;
    --muted: #6b7280;
    --bg: #f4f6fa;
    --white: #ffffff;
    --border: #e5e9f0;
    --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.05);
    --shadow: 0 1px 3px rgba(16, 24, 40, 0.08);
    --shadow-md: 0 4px 12px rgba(16, 24, 40, 0.08);
    --shadow-lg: 0 8px 24px rgba(16, 24, 40, 0.12);
    --radius: 12px;
    --nav-h: 56px;
    --font-serif: Georgia, Cambria, "Times New Roman", "Songti SC", "STSong", "SimSun", serif;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

html {
    scroll-behavior: smooth;
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }

    html {
        scroll-behavior: auto;
    }

    main section.reveal {
        opacity: 1;
        transform: none;
        transition: none;
    }
}

body {
    font-family: var(--font-serif);
    font-size: 15px;
    line-height: 1.75;
    color: var(--text);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
    transition: background-color 0.25s ease, color 0.25s ease;
}

::selection {
    background: rgba(37, 99, 235, 0.18);
}

:focus-visible {
    outline: 2px solid var(--accent);
    outline-offset: 2px;
    border-radius: 4px;
}

/* ===== Layout ===== */
.container {
    max-width: 920px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== Navigation ===== */
.topnav {
    background: rgba(255, 255, 255, 0.88);
    -webkit-backdrop-filter: blur(10px) saturate(1.5);
    backdrop-filter: blur(10px) saturate(1.5);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 100;
}

.topnav .container {
    display: flex;
    align-items: center;
    gap: 4px;
    min-height: var(--nav-h);
    padding: 0 24px;
    max-width: 920px;
}

.topnav a {
    color: var(--text-light);
    padding: 7px 14px;
    border-radius: 8px;
    border-bottom: none;
    font-family: var(--font-sans);
    font-size: 13.5px;
    font-weight: 500;
    letter-spacing: 0.02em;
    transition: color 0.2s, background 0.2s;
}

.topnav a:hover {
    color: var(--primary);
    background: rgba(22, 48, 92, 0.07);
    border-bottom: none;
}

.topnav a.active {
    color: var(--white);
    background: var(--primary);
}

.topnav a.lang {
    margin-left: auto;
    border: 1px solid var(--border);
    padding: 4px 12px;
    border-radius: 999px;
    font-size: 12.5px;
    color: var(--muted);
}

.topnav a.lang:hover {
    color: var(--primary);
    border-color: var(--primary);
    background: var(--white);
}

/* ===== Profile Section ===== */
.profile-section {
    margin-top: 24px;
    background: linear-gradient(135deg, #ffffff 0%, #edf3fc 100%);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 30px 32px;
    box-shadow: var(--shadow-md);
}

.profile-content {
    display: flex;
    gap: 32px;
    align-items: flex-start;
}

.profile-text {
    flex: 1;
    min-width: 0;
}

.profile-text h1 {
    font-size: 2rem;
    font-weight: 700;
    letter-spacing: -0.01em;
    color: var(--primary);
    margin: 0 0 8px 0;
    font-family: var(--font-sans);
}

.profile-text h2 {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.05em;
    color: var(--white);
    background: var(--primary);
    padding: 3px 14px;
    border-radius: 999px;
    margin: 0 0 18px 0;
}

.affiliation, .contact, .research-interests {
    margin-bottom: 14px;
}

.affiliation p, .contact p {
    margin: 0 0 3px 0;
    font-size: 14px;
    color: var(--text-light);
    overflow-wrap: anywhere;
}

.research-interests p {
    margin: 0;
    font-size: 14px;
    background: var(--accent-soft);
    border-left: 3px solid var(--accent);
    border-radius: 0 8px 8px 0;
    padding: 10px 14px;
}

/* Google Scholar stats in the profile section */
.scholar-stats {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 8px;
    margin-bottom: 14px;
    font-family: var(--font-sans);
    font-size: 13px;
}

.scholar-stats .scholar-link {
    font-weight: 600;
    color: var(--primary);
    margin-right: 2px;
}

.scholar-stat {
    color: var(--text-light);
    background: var(--amber-soft);
    border: 1px solid rgba(217, 119, 6, 0.28);
    border-radius: 999px;
    padding: 1px 11px;
    white-space: nowrap;
}

.scholar-stat strong {
    color: var(--amber);
}

/* Icon buttons row in the profile contact block */
.contact-icons {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 10px !important;
}

.contact-icons a {
    width: 32px;
    height: 32px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    border-radius: 9px;
    color: var(--text-light);
    background: var(--white);
    font-family: var(--font-sans);
    font-size: 9.5px;
    font-weight: 700;
    letter-spacing: 0.02em;
    box-shadow: var(--shadow-sm);
    transition: color 0.2s, border-color 0.2s, transform 0.2s, box-shadow 0.2s;
}

.contact-icons a:hover {
    color: var(--primary);
    border-color: var(--primary);
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

.contact-icons svg {
    width: 16px;
    height: 16px;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.8;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.contact-icons svg.fill {
    fill: currentColor;
    stroke: none;
}

/* Profile link chips at the top of the publications page */
.profile-links {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 12px !important;
}

.profile-links a {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 4px 12px;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--white);
    font-family: var(--font-sans);
    font-size: 12.5px;
    font-weight: 600;
    color: var(--text-light);
    transition: color 0.2s, border-color 0.2s, transform 0.2s, box-shadow 0.2s;
}

.profile-links a:hover {
    color: var(--primary);
    border-color: var(--primary);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}

.profile-links svg {
    width: 14px;
    height: 14px;
    fill: none;
    stroke: currentColor;
    stroke-width: 1.8;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.profile-links svg.fill {
    fill: currentColor;
    stroke: none;
}

/* footnote legend under the profile chips on the publications page */
.legend {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 20px;
    margin: 0;
    font-family: var(--font-sans);
    font-size: 12.5px;
    color: var(--muted);
}

.legend span {
    display: inline-flex;
    align-items: center;
    gap: 5px;
}

.legend sup {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 16px;
    height: 16px;
    font-size: 10.5px;
    font-weight: 700;
    border-radius: 5px;
    color: var(--primary);
    background: var(--accent-soft);
}

/* matching tint for the in-text author markers */
ol sup {
    color: var(--primary);
    font-weight: 600;
}

/* Yearly-citations bar chart (added by site.js from res/scholar.json) */
.gs-graph {
    display: inline-flex;
    align-items: flex-end;
}

.gs-graph rect {
    fill: var(--accent);
    opacity: 0.75;
}

.gs-graph rect:last-of-type {
    fill: var(--amber);
    opacity: 1;
}

/* Venue tags on the influential-papers list (added by site.js) */
.venue-tag {
    font-family: var(--font-sans);
    font-size: 0.72em;
    font-weight: 700;
    letter-spacing: 0.02em;
    white-space: nowrap;
    border-radius: 5px;
    padding: 0 6px;
    margin: 0 -1px;
    color: var(--vc, #475569);
    background: rgba(100, 116, 139, 0.10);
    background: color-mix(in srgb, var(--vc, #475569) 12%, transparent);
}

.v-cvpr { --vc: #2563eb; }
.v-iccv { --vc: #0f766e; }
.v-eccv { --vc: #7c3aed; }
.v-neurips { --vc: #15803d; }
.v-icml { --vc: #c2410c; }
.v-iclr { --vc: #be185d; }
.v-aaai { --vc: #dc2626; }
.v-journal { --vc: #475569; }

/* top journals (Nature/Cell portfolio, TPAMI, IJCV): gold with a hairline ring */
.v-top {
    --vc: #b45309;
    box-shadow: inset 0 0 0 1px rgba(180, 83, 9, 0.35);
    box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--vc) 35%, transparent);
}

/* Reveal-on-scroll animation (class added by site.js) */
main section.reveal {
    opacity: 0;
    transform: translateY(14px);
    transition: opacity 0.55s ease, transform 0.55s ease;
}

main section.reveal.in {
    opacity: 1;
    transform: none;
}

.profile-image {
    flex-shrink: 0;
}

.profile-image img {
    width: 150px;
    height: 150px;
    object-fit: cover;
    border-radius: 16px;
    border: 4px solid var(--white);
    box-shadow: var(--shadow-lg);
}

/* ===== Main Content ===== */
main.container {
    padding-top: 8px;
    padding-bottom: 48px;
}

section {
    margin-bottom: 24px;
}

main section:not(.profile-section) {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    padding: 24px 28px;
}

section h2 {
    position: relative;
    font-size: 1.18rem;
    font-weight: 600;
    color: var(--primary);
    margin: 0 0 16px 0;
    padding: 0 0 10px 14px;
    border-bottom: 1px solid var(--border);
    font-family: var(--font-sans);
}

section h2::before {
    content: "";
    position: absolute;
    left: 0;
    top: 5px;
    bottom: 14px;
    width: 4px;
    border-radius: 2px;
    background: linear-gradient(180deg, var(--accent), var(--primary));
}

section h2 strong {
    font-weight: 600;
}

section > p {
    margin: -6px 0 14px;
    font-size: 13px;
    color: var(--muted);
}

/* ===== Lists ===== */
ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

ul li {
    position: relative;
    padding: 5px 10px 5px 22px;
    margin-bottom: 6px;
    border-radius: 8px;
    font-size: 14px;
    line-height: 1.65;
    transition: background 0.15s;
}

ul li:hover {
    background: var(--accent-soft);
}

ul li::before {
    content: "•";
    position: absolute;
    left: 8px;
    color: var(--accent);
    font-weight: 700;
}

ul li p {
    margin: 0;
    display: inline;
}

ul li p + p {
    display: block;
    margin-top: 4px;
}

/* Ordered lists (publications page) */
ol {
    list-style: decimal;
    padding-left: 2.4em;
    margin: 0;
}

ol li {
    margin-bottom: 12px;
    padding: 2px 6px 2px 4px;
    border-radius: 6px;
    line-height: 1.65;
    overflow-wrap: break-word;
    transition: background-color 0.15s;
}

ol li:hover {
    background: var(--accent-soft);
}

ol li::marker {
    color: var(--primary-light);
    font-family: var(--font-sans);
    font-size: 0.85em;
    font-weight: 600;
}

ol li p {
    margin: 0;
}

/* Year headings inside the publication list */
ol > li.year-heading {
    list-style: none;
    margin: 30px 0 14px;
    padding-bottom: 6px;
    border-bottom: 1px solid var(--border);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 700;
    letter-spacing: 0.03em;
    color: var(--primary);
}

ol > li.year-heading:first-of-type {
    margin-top: 16px;
}

/* Anchor offset so sticky bars don't cover jump targets */
ol > li.year-heading[id^="year-"] {
    scroll-margin-top: calc(var(--nav-h) + 72px);
}

/* ===== Citation badge & resource chips (added by site.js) ===== */
a.cite-badge,
a.star-badge {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 0.78em;
    font-weight: 600;
    line-height: 1.5;
    color: var(--amber);
    background: var(--amber-soft);
    border: 1px solid rgba(217, 119, 6, 0.28);
    border-radius: 999px;
    padding: 0 9px;
    white-space: nowrap;
    transition: color 0.2s, background 0.2s;
}

a.star-badge::before {
    content: "★ ";
}

a.cite-badge::before {
    content: "❝ ";
}

a.cite-badge strong,
a.star-badge strong {
    font-weight: 700;
}

a.cite-badge:hover,
a.star-badge:hover {
    color: var(--white);
    background: var(--amber);
    border-color: var(--amber);
}

/* GitHub star count inside a code chip (added by site.js):
   turns the chip into a GitHub-style "code | ★ N" button */
a.res-chip .chip-stars {
    margin-left: 6px;
    padding-left: 7px;
    border-left: 1px solid rgba(37, 99, 235, 0.25);
    color: var(--amber);
    transition: color 0.2s, border-color 0.2s;
}

a.res-chip:hover .chip-stars {
    color: var(--white);
    border-left-color: rgba(255, 255, 255, 0.45);
}

a.res-chip {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 0.78em;
    font-weight: 600;
    line-height: 1.55;
    color: var(--accent);
    background: var(--accent-soft);
    border: 1px solid rgba(37, 99, 235, 0.22);
    border-radius: 6px;
    padding: 0 7px;
    margin: 0 0 0 1px;
    white-space: nowrap;
    transition: color 0.2s, background 0.2s;
}

a.res-chip:hover {
    color: var(--white);
    background: var(--accent);
    border-color: var(--accent);
}

/* ===== Paper search box (added by site.js) ===== */
.pubs-search {
    position: relative;
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 14px 0 4px;
}

.pubs-search svg {
    position: absolute;
    left: 11px;
    width: 15px;
    height: 15px;
    fill: none;
    stroke: var(--muted);
    stroke-width: 2;
    stroke-linecap: round;
    pointer-events: none;
}

.pubs-search input {
    flex: 1;
    max-width: 420px;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    color: var(--text);
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 7px 12px 7px 34px;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.pubs-search input:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-soft);
}

.pubs-search input::placeholder {
    color: var(--muted);
}

.pubs-search-count {
    font-family: var(--font-sans);
    font-size: 0.8rem;
    color: var(--muted);
    white-space: nowrap;
}

.pubs-no-results {
    font-size: 0.9rem;
    color: var(--muted);
    margin: 18px 0;
}

/* matched keywords while filtering the publication list */
ol li mark {
    background: var(--amber-soft);
    color: var(--amber);
    border-radius: 3px;
    padding: 0 1px;
}

/* ===== Year quick navigation (added by site.js) ===== */
.year-nav {
    position: sticky;
    top: calc(var(--nav-h) + 10px);
    z-index: 50;
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    padding: 10px 12px;
    margin: 6px 0 22px;
    background: rgba(255, 255, 255, 0.94);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    border: 1px solid var(--border);
    border-radius: 10px;
    box-shadow: var(--shadow-sm);
}

.year-nav a {
    font-family: var(--font-sans);
    font-size: 12px;
    font-weight: 600;
    color: var(--text-light);
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 2px 11px;
    transition: color 0.2s, background 0.2s, border-color 0.2s;
}

.year-nav a:hover {
    color: var(--white);
    background: var(--primary);
    border-color: var(--primary);
}

/* scrollspy: the year currently in view (class added by site.js) */
.year-nav a.active {
    color: var(--white);
    background: var(--primary);
    border-color: var(--primary);
}

/* ===== Links ===== */
a {
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: border-color 0.2s, color 0.2s;
}

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

/* Author-mark superscripts (# student, * corresponding) */
li sup {
    color: var(--accent);
    font-weight: 700;
}

/* ===== Text Widget (pubs.html / group pages) ===== */
.sys_txt {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 32px 36px;
    box-shadow: var(--shadow);
    margin-top: 24px;
    margin-bottom: 40px;
}

.sys_txt::after {
    content: "";
    display: table;
    clear: both;
}

.sys_txt p {
    margin: 0 0 12px 0;
    text-align: justify;
    text-justify: inter-word;
}

.sys_txt p:last-child {
    margin-bottom: 0;
}

/* Section titles inside the text widget ("Major Journal & Conference Papers" etc.) */
.sys_txt > p > b,
.sys_txt > div > p > b {
    display: inline-block;
    font-family: var(--font-sans);
    font-size: 1.12rem;
    color: var(--primary);
}

.sys_txt > p:has(> b) {
    margin-top: 30px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.sys_txt > p:first-child:has(> b) {
    margin-top: 0;
}

.sys_txt b {
    color: var(--primary);
    font-weight: 600;
}

/* Group-page subsection headings ("Faculty Members" etc.) */
.sys_txt h2 {
    position: relative;
    font-family: var(--font-sans);
    font-size: 1.18rem;
    font-weight: 600;
    color: var(--primary);
    margin: 34px 0 18px;
    padding: 0 0 10px 14px;
    border-bottom: 1px solid var(--border);
}

.sys_txt h2::before {
    content: "";
    position: absolute;
    left: 0;
    top: 5px;
    bottom: 14px;
    width: 4px;
    border-radius: 2px;
    background: linear-gradient(180deg, var(--accent), var(--primary));
}

.sys_txt h2:first-child {
    margin-top: 0;
}

/* ===== Member Cards (group pages) ===== */
.members-section {
    margin: 8px 0 26px;
    display: flex;
    justify-content: center;
}

.members-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 18px;
    justify-content: center;
    max-width: 100%;
}

.member-card {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    width: 240px;
    padding: 22px 16px 18px;
    display: flex;
    flex-direction: column;
    align-items: center;
    overflow: hidden;
    transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.member-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.member-photo {
    width: 96px;
    height: 96px;
    border-radius: 50%;
    margin-bottom: 12px;
    object-fit: cover;
    background: #f0f0f0;
    box-shadow: 0 0 0 3px var(--white), 0 0 0 4px var(--border);
    user-select: none;
    transition: transform 0.25s ease;
}

.member-card:hover .member-photo {
    transform: scale(1.06);
}

.member-name {
    font-family: var(--font-sans);
    font-size: 0.98rem;
    font-weight: 600;
    color: var(--text);
    text-align: center;
    margin-bottom: 6px;
    word-wrap: break-word;
    overflow-wrap: break-word;
    max-width: 100%;
}

.member-desc {
    font-family: var(--font-sans);
    font-size: 0.82rem;
    color: var(--text-light);
    text-align: center;
    line-height: 1.55;
    word-wrap: break-word;
    overflow-wrap: break-word;
    max-width: 100%;
}

.member-link {
    margin-top: auto;
    padding-top: 12px;
}

.member-link a {
    font-family: var(--font-sans);
    font-size: 0.82rem;
    font-weight: 600;
    color: var(--accent);
    border-bottom: none;
}

.member-link a:hover {
    color: var(--primary);
    border-bottom: 1px solid var(--primary);
}

/* ===== Project gallery (homepage "Selected Projects") ===== */
.gal {
    position: relative;
}

.gal-track {
    display: grid;
    grid-auto-flow: column;
    grid-template-rows: repeat(2, auto);
    /* ~4.3 columns visible: the sliver of the 5th column hints "swipe right" */
    grid-auto-columns: calc((100% - 3 * 14px) / 4.28);
    gap: 14px;
    overflow-x: auto;
    scroll-snap-type: x proximity;
    scrollbar-width: none;
    padding-bottom: 2px;
    /* fade the edge that has more content (JS toggles the state classes) */
    -webkit-mask-image: linear-gradient(90deg, #000 calc(100% - 44px), transparent);
    mask-image: linear-gradient(90deg, #000 calc(100% - 44px), transparent);
}

.gal.gal-mid .gal-track {
    -webkit-mask-image: linear-gradient(90deg, transparent, #000 44px, #000 calc(100% - 44px), transparent);
    mask-image: linear-gradient(90deg, transparent, #000 44px, #000 calc(100% - 44px), transparent);
}

.gal.gal-end .gal-track {
    -webkit-mask-image: linear-gradient(90deg, transparent, #000 44px);
    mask-image: linear-gradient(90deg, transparent, #000 44px);
}

.gal.gal-fit .gal-track {
    -webkit-mask-image: none;
    mask-image: none;
}

.gal-track::-webkit-scrollbar {
    display: none;
}

.gal-track a.gal-card {
    scroll-snap-align: start;
    display: flex;
    flex-direction: column;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform 0.18s ease, box-shadow 0.18s ease;
}

.gal-track a.gal-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
    border-bottom-color: var(--border);
}

.gal-media {
    display: block;
    aspect-ratio: 16 / 10;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    overflow: hidden;
}

.gal-media img,
.gal-media video {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 8px;
    box-sizing: border-box;
    display: block;
}

.gal-body {
    display: block;
    padding: 10px 12px 12px;
}

.gal-name {
    display: block;
    font-family: var(--font-sans);
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 5px;
}

.gal-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 5px;
    align-items: center;
}

.gal-topic {
    font-family: var(--font-sans);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    white-space: nowrap;
    border-radius: 5px;
    padding: 0 6px;
    color: var(--muted);
    box-shadow: inset 0 0 0 1px var(--border);
}

.gal-more {
    font-family: var(--font-sans);
    font-size: 0.85rem;
    margin: 10px 0 0;
}

/* Prev/next buttons (added by site.js; hidden without JS or when not scrollable) */
.gal-btn {
    position: absolute;
    top: -46px;
    right: 0;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: var(--white);
    color: var(--primary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0;
    box-shadow: var(--shadow-sm);
    transition: opacity 0.2s, background 0.2s, color 0.2s;
}

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

.gal-btn[disabled] {
    opacity: 0.35;
    pointer-events: none;
}

.gal-btn.gal-prev {
    right: 36px;
}

.gal-btn svg {
    width: 14px;
    height: 14px;
}

@media (max-width: 720px) {
    .gal-track {
        grid-auto-columns: calc((100% - 14px) / 2.28);
    }
}

/* ===== Footer ===== */
.bottombar {
    text-align: center;
    padding: 26px 0;
    color: var(--muted);
    font-family: var(--font-sans);
    font-size: 12px;
    letter-spacing: 0.08em;
    border-top: 1px solid var(--border);
    background: var(--white);
}

/* ===== Sup/Sub ===== */
sup, sub {
    font-size: 0.75em;
    line-height: 0;
}

/* ===== Responsive ===== */
@media (max-width: 720px) {
    .container {
        padding: 0 16px;
    }

    .profile-section {
        padding: 24px 20px;
    }

    .profile-content {
        flex-direction: column-reverse;
        align-items: center;
        text-align: center;
        gap: 20px;
    }

    .scholar-stats {
        justify-content: center;
    }

    .contact-icons {
        justify-content: center;
    }

    .profile-text h1 {
        font-size: 1.6rem;
    }

    .profile-image img {
        width: 120px;
        height: 120px;
    }

    main section:not(.profile-section) {
        padding: 18px 20px;
    }

    .sys_txt {
        padding: 22px 20px;
    }

    ol {
        padding-left: 2em;
    }

    .year-nav {
        flex-wrap: nowrap;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
    }

    .member-card {
        width: calc(50% - 9px);
        min-width: 170px;
    }
}

@media (max-width: 520px) {
    .topnav .container {
        flex-wrap: wrap;
        justify-content: center;
        padding: 8px 16px;
    }

    .topnav a.lang {
        margin-left: 0;
    }

    .topnav a {
        padding: 6px 10px;
        font-size: 13px;
    }

    .member-card {
        width: 100%;
        max-width: 300px;
    }
}

/* ===== Back-to-top button (added by site.js on long pages) ===== */
.back-to-top {
    position: fixed;
    right: 22px;
    bottom: 22px;
    z-index: 90;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--border);
    border-radius: 50%;
    background: var(--white);
    color: var(--text-light);
    box-shadow: var(--shadow-md);
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transform: translateY(8px);
    transition: opacity 0.25s, transform 0.25s, visibility 0.25s,
                color 0.2s, border-color 0.2s;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
    transform: none;
}

.back-to-top:hover {
    color: var(--primary);
    border-color: var(--primary);
}

.back-to-top svg {
    width: 18px;
    height: 18px;
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

/* ===== Dark mode (data-theme attribute; default follows system, toggle overrides) ===== */
:root[data-theme="dark"] {
    color-scheme: dark;
    --primary: #7ea4f0;
    --primary-light: #9db9f5;
    --accent: #7ea4f0;
    --accent-soft: rgba(126, 164, 240, 0.13);
    --amber: #e5a558;
    --amber-soft: rgba(229, 165, 88, 0.13);
    --text: #e5e9f0;
    --text-light: #b4bdc9;
    --muted: #8b95a6;
    --bg: #0e1319;
    --white: #171e28;
    --border: #2a3444;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.45);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.55);
}

[data-theme="dark"] .topnav {
    background: rgba(14, 19, 25, 0.88);
}

[data-theme="dark"] .topnav a:hover {
    background: rgba(126, 164, 240, 0.12);
}

[data-theme="dark"] .topnav a.active {
    color: #0e1319;
    background: var(--primary);
}

[data-theme="dark"] .profile-section {
    background: linear-gradient(135deg, #1b2434 0%, #141b27 100%);
}

[data-theme="dark"] .profile-text h2 {
    color: #0e1319;
}

[data-theme="dark"] .year-nav {
    background: rgba(23, 30, 40, 0.94);
}

[data-theme="dark"] .year-nav a:hover {
    color: #0e1319;
}

[data-theme="dark"] .year-nav a.active {
    color: #0e1319;
}

[data-theme="dark"] a.cite-badge,
[data-theme="dark"] a.star-badge {
    border-color: rgba(229, 165, 88, 0.35);
}

[data-theme="dark"] a.cite-badge:hover,
[data-theme="dark"] a.star-badge:hover {
    color: #0e1319;
}

[data-theme="dark"] a.res-chip {
    border-color: rgba(126, 164, 240, 0.3);
}

[data-theme="dark"] a.res-chip .chip-stars {
    border-left-color: rgba(126, 164, 240, 0.3);
}

[data-theme="dark"] a.res-chip:hover .chip-stars {
    color: #0e1319;
    border-left-color: rgba(14, 19, 25, 0.4);
}

[data-theme="dark"] a.res-chip:hover {
    color: #0e1319;
}

[data-theme="dark"] .v-cvpr { --vc: #7ea4f0; }
[data-theme="dark"] .v-iccv { --vc: #2dd4bf; }
[data-theme="dark"] .v-eccv { --vc: #a78bfa; }
[data-theme="dark"] .v-neurips { --vc: #4ade80; }
[data-theme="dark"] .v-icml { --vc: #fb923c; }
[data-theme="dark"] .v-iclr { --vc: #f472b6; }
[data-theme="dark"] .v-aaai { --vc: #f87171; }
[data-theme="dark"] .v-journal { --vc: #94a3b8; }

[data-theme="dark"] .v-top {
    --vc: #e5a558;
    box-shadow: inset 0 0 0 1px rgba(229, 165, 88, 0.4);
    box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--vc) 40%, transparent);
}

/* ===== Theme toggle button ===== */
.theme-toggle {
    margin-left: 6px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 30px;
    height: 30px;
    padding: 0;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: transparent;
    color: var(--muted);
    cursor: pointer;
    transition: color 0.2s, border-color 0.2s, background 0.2s;
}

.theme-toggle:hover {
    color: var(--primary);
    border-color: var(--primary);
    background: var(--accent-soft);
}

.theme-toggle svg {
    width: 15px;
    height: 15px;
    stroke: currentColor;
    fill: none;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
}

.theme-toggle .icon-sun {
    display: none;
}

:root[data-theme="dark"] .theme-toggle .icon-sun {
    display: block;
}

:root[data-theme="dark"] .theme-toggle .icon-moon {
    display: none;
}

/* ===== Print ===== */
@media print {
    :root {
        --primary: #16305c;
        --primary-light: #2c5282;
        --accent: #2563eb;
        --amber: #b45309;
        --text: #1f2937;
        --text-light: #4b5563;
        --muted: #6b7280;
        --bg: #ffffff;
        --white: #ffffff;
        --border: #e5e9f0;
    }

    body {
        background: white;
    }

    .topnav, .bottombar, .year-nav, .back-to-top, .pubs-search {
        display: none;
    }

    .container {
        max-width: 100%;
        padding: 0;
    }

    .sys_txt,
    main section:not(.profile-section),
    .profile-section {
        box-shadow: none;
        border: none;
        padding: 0;
    }

    a.cite-badge, a.star-badge, a.res-chip {
        border: none;
        padding: 0;
        color: var(--accent);
        background: none;
    }
}

/* ===== Utilities ===== */
.noscript-note {
    color: var(--muted);
    font-size: 13px;
    text-align: center;
    padding: 12px 0;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    clip-path: inset(50%);
    white-space: nowrap;
    border: 0;
}

/* ===== Projects page (projs.html / projs_cn.html) ===== */
.proj-hero h1 {
    position: relative;
    font-family: var(--font-sans);
    font-size: 1.18rem;
    font-weight: 600;
    color: var(--primary);
    margin: 26px 0 12px;
    padding: 0 0 10px 14px;
    border-bottom: 1px solid var(--border);
}
.proj-hero h1::before {
    content: "";
    position: absolute;
    left: 0;
    top: 3px;
    bottom: 13px;
    width: 4px;
    border-radius: 2px;
    background: linear-gradient(180deg, var(--accent), var(--primary));
}
.proj-hero .proj-sub {
    margin: 0;
    font-size: 13px;
    line-height: 1.7;
    color: var(--muted);
}
.proj-hero .legend { margin-top: 8px; }

.proj-grid {
    list-style: none;
    padding: 0;
    margin: 24px 0 10px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 20px;
}
@media (max-width: 720px) {
    .proj-grid { grid-template-columns: 1fr; }
}

li.proj-card {
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform 0.18s ease, box-shadow 0.18s ease;
}
li.proj-card:hover {
    background: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow-md);
}

.proj-media {
    display: block;
    aspect-ratio: 16 / 8.6;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    overflow: hidden;
}
.proj-media img,
.proj-media video {
    width: 100%;
    height: 100%;
    object-fit: contain;
    padding: 10px;
    box-sizing: border-box;
    display: block;
    transition: transform 0.25s ease;
}
li.proj-card:hover .proj-media img,
li.proj-card:hover .proj-media video { transform: scale(1.03); }

.proj-body {
    padding: 16px 18px 18px;
    display: flex;
    flex-direction: column;
    flex: 1;
}
.proj-meta { display: flex; flex-wrap: wrap; gap: 6px; align-items: center; }
.proj-topic {
    font-family: var(--font-sans);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    white-space: nowrap;
    border-radius: 5px;
    padding: 0 6px;
    color: var(--muted);
    box-shadow: inset 0 0 0 1px var(--border);
}

.proj-title {
    margin: 8px 0 6px;
    font-size: 1rem;
    font-weight: 700;
    line-height: 1.5;
    color: var(--text);
}
.proj-authors {
    margin: 0 0 8px;
    font-size: 0.84rem;
    line-height: 1.6;
    color: var(--muted);
}
.proj-desc {
    margin: 0 0 12px;
    font-size: 0.88rem;
    line-height: 1.7;
    color: var(--text-light);
    flex: 1;
}
.proj-links { margin: 0; }