/* HEATlab site styles. No framework: plain CSS, mobile first. */

:root {
    --gold: #FDB913;
    --gold-dark: #8a6400;   /* 5:1 contrast on all page backgrounds */
    --ink: #1d2126;
    --muted: #5b6370;
    --line: #e4e6ea;
    --band: #f6f7f9;
    --card: #ffffff;
    --radius: 12px;
    --wrap: 1120px;
    --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 76px; }
body { margin: 0; font: 16px/1.6 var(--font); color: var(--ink); background: #fff; }
img { max-width: 100%; height: auto; display: block; }
a { color: var(--gold-dark); text-underline-offset: 2px; }
a:hover { color: var(--ink); }
h1, h2, h3, h4 { line-height: 1.2; margin: 0 0 .5em; }
p { margin: 0 0 1em; }

.wrap { max-width: var(--wrap); margin: 0 auto; padding: 0 20px; }
.wrap.narrow { max-width: 760px; }
section { padding: 72px 0; }
.band { background: var(--band); }
.section-title { font-size: clamp(1.8rem, 3vw, 2.3rem); letter-spacing: -.01em; }
.section-lead { color: var(--muted); max-width: 720px; font-size: 1.08rem; margin-bottom: 2rem; }

/* --- Top bar --- */
.topbar { position: sticky; top: 0; z-index: 10; background: rgba(255,255,255,.94); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); }
.topbar-inner { display: flex; align-items: center; justify-content: space-between; height: 60px; gap: 16px; }
.brand img { height: 38px; width: auto; }
.topbar nav { display: flex; gap: 4px; flex-wrap: nowrap; overflow-x: auto; }
.topbar nav a { color: var(--ink); text-decoration: none; font-weight: 600; font-size: .95rem; padding: 6px 10px; border-radius: 8px; white-space: nowrap; }
.topbar nav a:hover { background: var(--band); }
.topbar .nav-join { background: var(--gold); }
.topbar .nav-join:hover { background: #ffcd45; }

/* --- Hero --- */
.hero {
    color: #fff; padding: 120px 0 96px;
    background: linear-gradient(90deg, rgba(20,22,26,.82) 0%, rgba(20,22,26,.55) 55%, rgba(20,22,26,.15) 100%),
                url("../img/hero.jpg") center 30% / cover no-repeat;
}
.hero-inner { max-width: var(--wrap); }
.eyebrow { text-transform: uppercase; letter-spacing: .12em; font-size: .85rem; font-weight: 700; color: var(--gold); margin-bottom: .6rem; }
.hero h1 { font-size: clamp(2.1rem, 5vw, 3.6rem); max-width: 14ch; letter-spacing: -.02em; }
.hero-lead { font-size: clamp(1.1rem, 2vw, 1.3rem); max-width: 46ch; opacity: .95; margin-bottom: 1.6rem; }
.hero-sub { display: inline-block; margin-top: .5rem; font-size: .9em; color: #ffe08a; }
.status-pill { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); background: #fff; text-decoration: none;
    font-weight: 600; font-size: .95rem; padding: 8px 16px; border-radius: 999px; }
.status-pill:hover { color: var(--ink); background: #fff7df; }
.dot { width: 9px; height: 9px; border-radius: 50%; background: #9aa1ab; }

/* --- Students band --- */
.stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin-bottom: 40px; }
@media (max-width: 719px) { .stat:last-child:nth-child(odd) { grid-column: 1 / -1; } }  /* phones: 2 columns, last card spans */
.stat { background: var(--card); border-radius: var(--radius); padding: 18px 20px; border: 1px solid var(--line); }
.stat strong { display: block; font-size: 2.2rem; line-height: 1.1; color: var(--ink); }
.stat strong::after { content: ""; display: block; width: 28px; height: 3px; background: var(--gold); margin: 8px 0 6px; }
.stat span { color: var(--muted); font-size: .95rem; }
.students-body { display: grid; gap: 32px; align-items: center; }
.students-body h2 { font-size: 1.7rem; }
.video { position: relative; padding: 0; border: 0; border-radius: var(--radius); overflow: hidden; cursor: pointer; background: #000; aspect-ratio: 16 / 9; width: 100%; }
.video img { width: 100%; height: 100%; object-fit: cover; opacity: .9; }
.video iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }
.play { position: absolute; left: 50%; top: 50%; width: 68px; height: 48px; transform: translate(-50%, -50%); background: var(--gold); border-radius: 12px; }
.play::after { content: ""; position: absolute; left: 27px; top: 14px; border-left: 18px solid var(--ink); border-top: 10px solid transparent; border-bottom: 10px solid transparent; }
.video:hover .play { background: #ffcd45; }

/* --- Research themes --- */
.themes { display: grid; gap: 24px; }
.theme { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; display: flex; flex-direction: column; }
.theme > img { width: 100%; aspect-ratio: 16 / 9; object-fit: cover; background: #fff; border-bottom: 1px solid var(--line); }
.theme-body { padding: 20px 22px 22px; display: flex; flex-direction: column; flex: 1; }
.theme h3 { font-size: 1.3rem; }
.theme-body > p { color: var(--muted); }
.theme-projects-label { font-size: .78rem; text-transform: uppercase; letter-spacing: .08em; font-weight: 700; color: var(--muted); margin: .4rem 0 .4rem; }
.theme details { border-top: 1px solid var(--line); }
.theme summary { cursor: pointer; padding: 9px 0; font-weight: 600; list-style: none; display: flex; justify-content: space-between; gap: 12px; }
.theme summary::-webkit-details-marker { display: none; }
.theme summary::after { content: "+"; color: var(--gold-dark); font-weight: 700; }
.theme details[open] summary::after { content: "–"; }
.theme details p { font-size: .95rem; color: var(--muted); margin-bottom: .6rem; }
.project-people { font-size: .9rem !important; color: var(--ink) !important; }
.project-papers { margin: 0 0 .8rem; padding-left: 1.1rem; font-size: .9rem; }
.project-papers span { color: var(--muted); }
.theme-papers { margin-top: auto; align-self: flex-start; background: none; border: 0; padding: 14px 0 0; font: inherit; font-weight: 700; color: var(--gold-dark); cursor: pointer; }
.theme-papers:hover { color: var(--ink); }

/* --- Gallery --- */
.gallery-section { padding: 0 0 72px; }
.gallery { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.gallery-item { display: block; border-radius: 10px; overflow: hidden; aspect-ratio: 4 / 3; }
.gallery-item img { width: 100%; height: 100%; object-fit: cover; transition: transform .3s; }
.gallery-item:hover img { transform: scale(1.04); }
.gallery-item:nth-child(7) img { object-position: 50% 25%; }
.lightbox { padding: 0; border: 0; background: transparent; max-width: 100vw; max-height: 100vh; width: 100vw; height: 100vh; overflow: hidden; }
.lightbox::backdrop { background: rgba(0,0,0,.9); }
.lightbox-figure { margin: 0; height: 100%; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 12px; padding: 56px 72px 24px; }
.lightbox img { max-width: 100%; max-height: calc(100vh - 130px); border-radius: 8px; object-fit: contain; }
.lightbox figcaption { color: #e6e8eb; font-size: .95rem; text-align: center; max-width: 70ch; }
.lightbox-count { color: #9aa1ab; margin-left: 8px; white-space: nowrap; }
.lightbox-nav { position: fixed; top: 50%; transform: translateY(-50%); width: 52px; height: 52px; border-radius: 50%; border: 0;
    background: rgba(255,255,255,.12); color: #fff; font-size: 2.2rem; line-height: 1; cursor: pointer; }
.lightbox-nav:hover, .lightbox-nav:focus-visible { background: var(--gold); color: var(--ink); }
.lightbox-prev { left: 16px; }
.lightbox-next { right: 16px; }
.lightbox-close { position: fixed; top: 12px; right: 18px; font-size: 2.4rem; line-height: 1; color: #fff; background: none; border: 0; cursor: pointer; }
@media (max-width: 560px) {
    .lightbox-figure { padding: 56px 12px 24px; }
    .lightbox-nav { top: auto; bottom: 18px; transform: none; }
}

/* --- Alumni --- */
.outcomes { font-size: 1.15rem; background: #fff8e1; border-left: 5px solid var(--gold); border-radius: 8px; padding: 14px 18px; max-width: 720px; }
.year { font-size: 1rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin: 28px 0 12px; display: flex; align-items: center; gap: 12px; }
.year::after { content: ""; flex: 1; height: 1px; background: var(--line); }
.alumni { list-style: none; padding: 0; margin: 0; display: grid; grid-template-columns: 1fr; gap: 10px; }
.alum { display: flex; gap: 14px; align-items: flex-start; padding: 12px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--card); }
.alum img, .initials { width: 56px; height: 56px; border-radius: 50%; flex: 0 0 56px; object-fit: cover; }
.initials { display: grid; place-items: center; background: #fff3cf; color: #8a6400; font-weight: 700; }
.alum p { margin: 0; font-size: .9rem; color: var(--muted); }
.alum .alum-name { font-weight: 700; color: var(--ink); font-size: 1rem; }
.alum .alum-now, .alum .alum-degree { position: relative; padding-left: 20px; margin-top: 4px; }
.alum .alum-now { color: var(--ink); font-weight: 600; }
.alum .alum-now::before, .alum .alum-degree::before { content: ""; position: absolute; left: 0; top: 3px; width: 14px; height: 14px; background: var(--gold-dark); }
/* briefcase (now) and graduation cap (degrees), as masks so they take the gold color */
.alum .alum-now::before { -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M10 3h4a2 2 0 0 1 2 2v1h4a2 2 0 0 1 2 2v4H2V8a2 2 0 0 1 2-2h4V5a2 2 0 0 1 2-2zm0 3h4V5h-4v1zM2 14h8v2h4v-2h8v5a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2v-5z'/%3E%3C/svg%3E") center / contain no-repeat; mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M10 3h4a2 2 0 0 1 2 2v1h4a2 2 0 0 1 2 2v4H2V8a2 2 0 0 1 2-2h4V5a2 2 0 0 1 2-2zm0 3h4V5h-4v1zM2 14h8v2h4v-2h8v5a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2v-5z'/%3E%3C/svg%3E") center / contain no-repeat; }
.alum .alum-degree::before { -webkit-mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M12 3 1 9l11 6 9-4.9V17h2V9L12 3zM5 13.2v3.8c0 1.7 3.1 4 7 4s7-2.3 7-4v-3.8l-7 3.8-7-3.8z'/%3E%3C/svg%3E") center / contain no-repeat; mask: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M12 3 1 9l11 6 9-4.9V17h2V9L12 3zM5 13.2v3.8c0 1.7 3.1 4 7 4s7-2.3 7-4v-3.8l-7 3.8-7-3.8z'/%3E%3C/svg%3E") center / contain no-repeat; }
.alum-linkedin { display: inline-flex; vertical-align: -2px; margin-left: 6px; color: #0a66c2; }
.alum-linkedin:hover { color: var(--ink); }
.alum-web { color: var(--gold-dark); }

/* --- Publications --- */
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 8px; }
.chip { font: inherit; font-size: .92rem; border: 1px solid #cfd3d9; background: #fff; color: var(--ink); border-radius: 999px; padding: 6px 14px; cursor: pointer; }
.chip span { color: var(--muted); font-size: .8rem; }
.chip:hover { border-color: var(--gold); }
.chip.active { background: var(--gold); border-color: var(--gold); font-weight: 700; }
.chip.active span { color: var(--ink); }
.pub { padding: 14px 0; border-bottom: 1px solid var(--line); }
.pub h4 { font-size: 1.05rem; margin-bottom: .3em; }
.pub p { margin: 0; font-size: .93rem; color: var(--muted); }
.pub b { color: var(--ink); }
.pub-year { margin-top: 32px; }

/* --- Join --- */
#join { padding-top: 64px; }
.notice { background: #fff8e1; border: 1px solid #f5d77a; border-left: 6px solid var(--gold); border-radius: var(--radius); padding: 20px 22px; margin-bottom: 24px; }
.notice strong { display: block; font-size: 1.15rem; margin-bottom: 6px; }
.notice p { margin: 0; }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; padding: 16px 0; font-weight: 700; list-style: none; display: flex; justify-content: space-between; gap: 16px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--gold-dark); font-size: 1.3rem; line-height: 1; }
.faq details[open] summary::after { content: "–"; }
.faq details p { color: var(--muted); }

/* --- Footer --- */
.footer { background: var(--ink); color: #c9ced6; padding: 32px 0; font-size: .92rem; }
.footer-inner { display: flex; align-items: center; gap: 20px; flex-wrap: wrap; }
.footer img { width: 56px; height: 56px; }
.footer p { margin: 0; }
.footer a { color: #fff; }

/* --- Larger screens --- */
@media (min-width: 720px) {
    .stats { grid-template-columns: repeat(3, 1fr); }
    .students-body { grid-template-columns: 1.1fr 1fr; gap: 48px; }
    .gallery { grid-template-columns: repeat(4, 1fr); }
    .alumni { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 1000px) {
    .stats { grid-template-columns: repeat(5, 1fr); }
    .themes { grid-template-columns: repeat(3, 1fr); }
    .alumni { grid-template-columns: repeat(3, 1fr); }
}
.short { display: none; }
@media (max-width: 560px) {
    .wrap { padding: 0 16px; }
    .brand img { height: 28px; }
    .topbar-inner { gap: 8px; }
    .topbar nav { gap: 2px; }
    .topbar nav a { padding: 6px 7px; font-size: .88rem; }
    .long { display: none; }
    .short { display: inline; }
    .alumni { gap: 0; }
    .alum { border: 0; border-bottom: 1px solid var(--line); border-radius: 0; padding: 10px 0; background: none; align-items: center; }
    .alum img, .initials { width: 44px; height: 44px; flex-basis: 44px; font-size: .85rem; }
    section { padding: 56px 0; }
    .hero { padding: 88px 0 72px; }
}
@media (prefers-reduced-motion: reduce) {
    html { scroll-behavior: auto; }
    .gallery-item img { transition: none; }
}