/* ==========================================================
   AISy Lab — main stylesheet
   Change the brand by editing the tokens in :root.
   ========================================================== */

:root {
  --accent: #4b3fb5;
  --accent-soft: #ecebfa;
  --bg: #ffffff;
  --bg-alt: #f6f6f9;
  --surface: #ffffff;
  --text: #1c1b22;
  --text-muted: #5f5d6b;
  --border: #e3e2ea;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(20, 18, 40, .04), 0 4px 16px rgba(20, 18, 40, .05);
  --max: 1080px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --accent: #a59cf5;
    --accent-soft: #2a2645;
    --bg: #121117;
    --bg-alt: #19181f;
    --surface: #1d1c24;
    --text: #ebeaf2;
    --text-muted: #a3a1b2;
    --border: #2e2c38;
    --shadow: none;
  }
}

/* ---------- Base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.6;
  color: var(--text);
  background: var(--bg);
}
img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.2; letter-spacing: -0.01em; margin: 0 0 .5em; }
h1 { font-size: clamp(2rem, 4vw, 2.75rem); }
h2 { font-size: 1.5rem; }
h3 { font-size: 1.1rem; }
p { margin: 0 0 1em; }
pre, code { font-family: var(--mono); font-size: .85em; }
[hidden] { display: none !important; }

.container { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
main.container { padding-top: 48px; padding-bottom: 80px; min-height: 60vh; }
.muted { color: var(--text-muted); }
.small { font-size: .9rem; }
.lead { font-size: 1.15rem; color: var(--text-muted); max-width: 46em; }
.eyebrow {
  font-size: .8rem; font-weight: 600; letter-spacing: .08em;
  text-transform: uppercase; color: var(--accent); margin-bottom: .75em;
  display: flex; gap: 12px; align-items: center;
}
.skip-link { position: absolute; left: -999px; }
.skip-link:focus { left: 16px; top: 16px; z-index: 10; background: var(--surface); padding: 8px 12px; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 5;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.header-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 1.1rem; color: var(--text); }
.brand:hover { text-decoration: none; }
/* the logo is black on transparent; flip it so it stays visible on the dark background */
@media (prefers-color-scheme: dark) { .brand-logo { filter: invert(1); } }
.site-nav { display: flex; gap: 28px; }
.site-nav a { color: var(--text-muted); font-weight: 500; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--text); text-decoration: none; }
.site-nav a[aria-current="page"] { box-shadow: inset 0 -2px 0 var(--accent); }
.nav-toggle, .nav-toggle-label { display: none; }

@media (max-width: 640px) {
  .nav-toggle-label {
    display: block; width: 28px; height: 20px; position: relative; cursor: pointer;
  }
  .nav-toggle-label span, .nav-toggle-label span::before, .nav-toggle-label span::after {
    content: ""; position: absolute; left: 0; width: 100%; height: 2px; background: var(--text);
  }
  .nav-toggle-label span { top: 9px; }
  .nav-toggle-label span::before { top: -8px; }
  .nav-toggle-label span::after { top: 8px; }
  .site-nav {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; gap: 0; background: var(--bg); border-bottom: 1px solid var(--border);
  }
  .site-nav a { padding: 14px 24px; }
  .nav-toggle:checked ~ .site-nav { display: flex; }
}

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--border); background: var(--bg-alt); padding: 32px 0; font-size: .92rem; }
.footer-inner { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
.footer-links { display: flex; flex-direction: column; gap: 4px; text-align: right; }
@media (max-width: 640px) { .footer-links { text-align: left; } }

/* ---------- Buttons, tags ---------- */
.btn {
  display: inline-block; padding: 10px 18px; border-radius: 999px;
  background: var(--accent); color: #fff; font-weight: 600; font-size: .95rem;
  border: 1px solid var(--accent);
}
@media (prefers-color-scheme: dark) { .btn { color: #121117; } }
.btn:hover { text-decoration: none; filter: brightness(1.08); }
.btn-ghost { background: transparent; color: var(--accent); }
.link-row { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 24px; }

.tags { list-style: none; padding: 0; margin: 12px 0 0; display: flex; flex-wrap: wrap; gap: 6px; }
.tag, .chip {
  --area: var(--accent);
  font-size: .78rem; font-weight: 600; padding: 3px 10px; border-radius: 999px;
  color: var(--area);
  background: color-mix(in srgb, var(--area) 12%, transparent);
}
.status { font-size: .75rem; padding: 2px 10px; border-radius: 999px; background: var(--accent-soft); }
.status-past { color: var(--text-muted); background: var(--bg-alt); }

/* ---------- Layout pieces ---------- */
.hero { padding: 40px 0 24px; }
.hero-logos { display: flex; align-items: center; gap: 32px; margin-bottom: 24px; }
.hero-logos img { width: auto; }
/* both logos are black on transparent; flip them for the dark background */
@media (prefers-color-scheme: dark) { .hero-logos img { filter: invert(1); } }
.hero h1 { font-size: clamp(2.3rem, 5vw, 3.4rem); max-width: 16em; }
.page-header { margin-bottom: 32px; }
.section { margin-top: 64px; }
.section-head { display: flex; justify-content: space-between; align-items: baseline; gap: 16px; }
.section-head a { white-space: nowrap; font-size: .95rem; }
.breadcrumb { font-size: .9rem; margin-bottom: 16px; }

.grid { display: grid; gap: 20px; }
.grid-3 { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); }

.card {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: var(--radius); box-shadow: var(--shadow); padding: 22px;
  color: inherit;
}
.card p { color: var(--text-muted); font-size: .95rem; margin: 0; }
.area-card h3 { margin-top: 14px; }
.area-dot { display: block; width: 28px; height: 4px; border-radius: 2px; background: var(--area); }

.project-card { padding: 0; overflow: hidden; display: flex; flex-direction: column; transition: transform .15s, border-color .15s; }
.project-card:hover { text-decoration: none; transform: translateY(-2px); border-color: var(--accent); }
.project-card .card-body { padding: 20px 22px 22px; }
.project-thumb { width: 100%; aspect-ratio: 16 / 7; object-fit: cover; }
.project-thumb-empty {
  background:
    radial-gradient(circle at 20% 30%, color-mix(in srgb, var(--area) 55%, transparent) 0 2px, transparent 3px) 0 0 / 22px 22px,
    linear-gradient(135deg, color-mix(in srgb, var(--area) 30%, var(--surface)), color-mix(in srgb, var(--area) 8%, var(--surface)));
}
.project-hero { border-radius: var(--radius); margin: 8px 0 32px; }

.area-list { display: grid; gap: 4px; }
.area-row { border-left: 3px solid var(--area); padding: 6px 0 6px 20px; margin-bottom: 20px; }
.area-row p { margin-bottom: .4em; }

.prose { max-width: 46em; }
.prose h2 { margin-top: 1.6em; }

.callout { background: var(--accent-soft); border-radius: var(--radius); padding: 28px 32px; }
.callout p { margin: 0; }

/* ---------- Publications ---------- */
.filter-bar { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 8px; }
.chip { border: 1px solid transparent; cursor: pointer; font-family: inherit; font-size: .85rem; padding: 6px 14px; }
.chip[data-filter="all"] { color: var(--text); background: var(--bg-alt); }
.chip[aria-pressed="true"] { border-color: currentColor; }

.pub-year h2 { margin-top: 48px; padding-bottom: 8px; border-bottom: 1px solid var(--border); color: var(--text-muted); font-size: 1.2rem; }
.pub-list { list-style: none; padding: 0; margin: 0; }
.pub { padding: 18px 0; border-bottom: 1px solid var(--border); }
.pub:last-child { border-bottom: 0; }
.pub p { margin: 0; }
.pub-title { font-weight: 600; }
.pub-title a { color: var(--text); }
.pub-title a:hover { color: var(--accent); }
.pub-authors, .pub-venue { color: var(--text-muted); font-size: .93rem; }
.lab-author { color: var(--text); font-weight: 600; }
.award {
  font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .05em;
  color: #9a6400; background: #fdf0d2; padding: 2px 8px; border-radius: 4px; margin-left: 6px; vertical-align: 2px;
}
@media (prefers-color-scheme: dark) { .award { color: #f3c56b; background: #3a2e14; } }
.pub-links { display: flex; flex-wrap: wrap; align-items: flex-start; gap: 6px 14px; margin-top: 6px; font-size: .85rem; font-family: var(--mono); }
.bibtex summary { cursor: pointer; color: var(--accent); list-style: none; }
.bibtex summary::-webkit-details-marker { display: none; }
.bibtex[open] { flex-basis: 100%; }
.bibtex pre { background: var(--bg-alt); border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px; overflow-x: auto; margin: 8px 0 0; }

/* ---------- People ---------- */
.people-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 28px 32px; }
.person { display: flex; gap: 18px; align-items: flex-start; }
.avatar { width: 96px; height: 96px; border-radius: 50%; object-fit: cover; flex: none; background: var(--bg-alt); }
.person h3 { margin: 4px 0 2px; }
.person h3 a { color: var(--text); }
.person p { margin: 0; font-size: .93rem; }
.person-role { color: var(--accent); font-weight: 500; }
.person-interests { color: var(--text-muted); margin-top: 4px !important; }
.person-projects { margin-top: 8px; }
.person-links { display: flex; gap: 12px; margin-top: 6px !important; font-size: .85rem !important; font-family: var(--mono); }
.alumni { padding-left: 1.2em; }
.alumni li { margin-bottom: 6px; }