/* XRT project site. Layout and tokens follow sew-mimic.com (shadcn "slate"). */
:root {
  --bg: #ffffff;
  --fg: #020618;
  --muted: #f1f5f9;
  --muted-fg: #62748e;
  --subtle-fg: #45556c;
  --border: #e2e8f0;
  --card: #ffffff;
  --card-soft: #f8fafc;
  --accent: #e2e8f0;
  --dark-band: #18181b;
  --dark-band-fg: #fafafa;
  --code-bg: #f1f5f9;
  /* section tags: XRT framework vs the dual-XRT study */
  --xrt: #2563eb;
  --xrt-soft: #eff6ff;
  --study: #0f766e;
  --study-soft: #f0fdfa;
  --tactile: #3265ab;
  --audio: #b54c41;
  --radius: 12px;
  --font-sans: ui-sans-serif, system-ui, -apple-system, "Segoe UI", "Noto Sans", Roboto, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #020618; --fg: #f8fafc; --muted: #1d293d; --muted-fg: #90a1b9; --subtle-fg: #cad5e2;
    --border: #ffffff1a; --card: #0f172b; --card-soft: #0f172b; --accent: #1d293d;
    --dark-band: #000000; --code-bg: #1d293d;
    --xrt: #60a5fa; --xrt-soft: #172554; --study: #2dd4bf; --study-soft: #042f2e;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #020618; --fg: #f8fafc; --muted: #1d293d; --muted-fg: #90a1b9; --subtle-fg: #cad5e2;
  --border: #ffffff1a; --card: #0f172b; --card-soft: #0f172b; --accent: #1d293d;
  --dark-band: #000000; --code-bg: #1d293d;
  --xrt: #60a5fa; --xrt-soft: #172554; --study: #2dd4bf; --study-soft: #042f2e;
  color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0; background: var(--bg); color: var(--fg); font-family: var(--font-sans);
  line-height: 1.5; -webkit-font-smoothing: antialiased;
  display: flex; flex-direction: column; min-height: 100vh;
}
main { flex: 1; }
img, video, iframe { max-width: 100%; display: block; }
img { height: auto; }
a { color: inherit; }
code, pre, .mono { font-family: var(--font-mono); }
:focus-visible { outline: 2px solid var(--xrt); outline-offset: 2px; border-radius: 4px; }

/* ---------- header / nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 30; background: color-mix(in oklab, var(--bg) 92%, transparent);
  backdrop-filter: saturate(1.4) blur(8px); border-bottom: 1px solid transparent;
}
.site-header.scrolled { border-bottom-color: var(--border); }
.nav-wrap {
  display: grid; grid-template-columns: 1fr auto 1fr; align-items: center;
  gap: 16px; padding: 10px 24px; max-width: 1400px; margin: 0 auto;
}
.brand { font-weight: 700; text-decoration: none; display: inline-flex; align-items: center; gap: 8px; white-space: nowrap; }
.brand img { width: 26px; height: 26px; }
.nav { display: flex; gap: 4px; flex-wrap: wrap; justify-content: center; }
.nav a {
  text-decoration: none; font-size: 15px; padding: 8px 16px; border-radius: 8px; color: var(--fg);
  transition: background .15s;
}
.nav a:hover { background: var(--muted); }
.nav a[aria-current="page"] { background: var(--accent); }
.nav-right { display: flex; justify-content: flex-end; gap: 6px; align-items: center; }
.icon-btn {
  display: inline-flex; align-items: center; justify-content: center; width: 36px; height: 36px;
  border-radius: 8px; border: 1px solid var(--border); background: var(--bg); color: var(--fg); cursor: pointer;
  text-decoration: none;
}
.icon-btn:hover { background: var(--muted); }
.icon-btn svg { width: 18px; height: 18px; }
.menu-btn { display: none; }
@media (max-width: 860px) {
  .nav-wrap { grid-template-columns: 1fr auto; padding: 10px 16px; }
  .menu-btn { display: inline-flex; }
  .nav {
    display: none; grid-column: 1 / -1; flex-direction: column; align-items: stretch; padding-bottom: 8px;
  }
  .nav.open { display: flex; }
  .nav-right { grid-row: 1; grid-column: 2; }
}

/* ---------- layout ---------- */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.narrow { max-width: 900px; margin: 0 auto; padding: 0 24px; }
@media (max-width: 600px) { .container, .narrow { padding: 0 16px; } }

/* ---------- hero ---------- */
.hero { text-align: center; padding-top: 56px; padding-bottom: 24px; }
.hero h1 {
  font-size: clamp(2rem, 5.2vw, 3.1rem); line-height: 1.05; letter-spacing: -0.035em; margin: 0 auto;
  max-width: 980px; font-weight: 700;
}
.hero h1 .name {
  font-family: var(--font-mono); background: var(--muted); padding: 0 .18em; border-radius: 6px;
  letter-spacing: 0;
}
.hero h1 .sub { display: block; color: var(--muted-fg); font-weight: 400; margin-top: 4px; }
.hero .lede { color: var(--muted-fg); font-size: 1.1rem; max-width: 760px; margin: 22px auto 0; }
.btn-row { display: flex; gap: 10px; justify-content: center; flex-wrap: wrap; margin-top: 24px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px; padding: 9px 16px; border-radius: 999px;
  border: 1px solid var(--border); background: var(--bg); text-decoration: none; font-size: 14px;
  font-weight: 500; cursor: pointer; color: var(--fg);
}
.btn:hover { background: var(--muted); }
.btn.primary { background: var(--fg); color: var(--bg); border-color: var(--fg); }
.btn.primary:hover { opacity: .9; }
.btn svg { width: 16px; height: 16px; }
.btn[aria-disabled="true"] { opacity: .55; pointer-events: none; }

/* ---------- the XRT vs dual-XRT explainer ---------- */
.scope { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin: 40px auto 8px; max-width: 1040px; }
@media (max-width: 760px) { .scope { grid-template-columns: 1fr; } }
.scope-card {
  border: 1px solid var(--border); border-radius: var(--radius); padding: 22px 22px 18px; background: var(--card);
  border-top: 4px solid var(--c); text-decoration: none; display: flex; flex-direction: column; gap: 8px;
  transition: box-shadow .15s, transform .15s;
}
.scope-card:hover { box-shadow: 0 10px 30px -12px #0f172a33; transform: translateY(-1px); }
.scope-card.xrt { --c: var(--xrt); }
.scope-card.study { --c: var(--study); }
.scope-card h2 { margin: 0; font-size: 1.25rem; }
.scope-card p { margin: 0; color: var(--subtle-fg); font-size: .95rem; }
.scope-card .diagram { display: flex; align-items: center; gap: 8px; font-size: 13px; color: var(--muted-fg); flex-wrap: wrap; margin: 4px 0; }
.scope-card .diagram span.box { border: 1px solid var(--border); border-radius: 6px; padding: 2px 8px; background: var(--card-soft); color: var(--fg); }
.scope-card .go { margin-top: auto; font-size: 14px; font-weight: 600; color: var(--c); }

.tag {
  display: inline-flex; align-items: center; gap: 6px; font-size: 12px; font-weight: 600; letter-spacing: .02em;
  text-transform: uppercase; padding: 3px 10px; border-radius: 999px; width: fit-content;
}
.tag::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: currentColor; }
.tag.xrt { color: var(--xrt); background: var(--xrt-soft); }
.tag.study { color: var(--study); background: var(--study-soft); }
.tag.paper { color: var(--muted-fg); background: var(--muted); text-transform: none; letter-spacing: 0; font-weight: 500; }
.tag.paper::before { display: none; }

/* ---------- claim + carousel blocks (as on sew-mimic.com) ---------- */
.block { padding: 48px 0 8px; }
.block header { text-align: center; max-width: 900px; margin: 0 auto 18px; display: flex; flex-direction: column; align-items: center; gap: 10px; }
.block h3 { font-size: clamp(1.1rem, 2.2vw, 1.3rem); line-height: 1.45; margin: 0; font-weight: 700; }
.block h3 a { text-underline-offset: 3px; }

.carousel { position: relative; max-width: 800px; margin: 0 auto; }
.carousel .viewport { overflow: hidden; border-radius: var(--radius); }
.carousel .track { display: flex; transition: transform .45s cubic-bezier(.2,.7,.2,1); }
.carousel .slide { min-width: 100%; }
.frame {
  position: relative; aspect-ratio: 16 / 9; background: var(--card-soft); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden; box-shadow: 0 8px 24px -14px #0f172a40;
}
.frame video, .frame iframe, .frame img { width: 100%; height: 100%; object-fit: contain; border: 0; background: #0b0b0c; }
.frame img.light { background: #fff; }
.slide .cap { font-size: 14px; color: var(--muted-fg); margin: 10px 2px 0; }
.carousel .arrow {
  position: absolute; top: calc(50% - 30px); width: 34px; height: 34px; border-radius: 50%;
  border: 1px solid var(--border); background: var(--bg); display: inline-flex; align-items: center; justify-content: center;
  cursor: pointer; color: var(--fg); box-shadow: 0 1px 2px #0000000d;
}
.carousel .arrow:disabled { opacity: .4; cursor: default; }
.carousel .arrow.prev { left: -52px; }
.carousel .arrow.next { right: -52px; }
.carousel .arrow svg { width: 16px; height: 16px; }
@media (max-width: 960px) {
  .carousel .arrow { top: auto; bottom: -46px; }
  .carousel .arrow.prev { left: calc(50% - 44px); }
  .carousel .arrow.next { right: calc(50% - 44px); }
  .carousel.multi { margin-bottom: 48px; }
}
.sound-btn {
  position: absolute; right: 10px; bottom: 10px; z-index: 2; display: inline-flex; gap: 6px; align-items: center;
  font: 600 12px var(--font-sans); padding: 6px 10px; border-radius: 999px; border: 0; cursor: pointer;
  background: #000000b3; color: #fff;
}
.sound-btn svg { width: 14px; height: 14px; }

/* ---------- dark band with the full video ---------- */
.band { background: var(--dark-band); color: var(--dark-band-fg); padding: 56px 0 64px; margin-top: 64px; }
.band h2 { margin: 0 0 6px; font-size: 1.5rem; }
.band p { margin: 0 0 18px; color: #a1a1aa; }
.band .frame { border-color: #ffffff1a; background: #0a0a0a; }

/* ---------- generic content pages ---------- */
.page-head { padding-top: 48px; padding-bottom: 12px; }
.page-head h1 { font-size: clamp(1.9rem, 4vw, 2.5rem); margin: 10px 0 8px; letter-spacing: -0.02em; line-height: 1.15; }
.page-head p.lede { color: var(--muted-fg); font-size: 1.08rem; margin: 0; max-width: 820px; }
.authors-line { color: var(--subtle-fg); margin-top: 12px; font-size: 15px; }
.authors-line sup { color: var(--muted-fg); }
.affil { color: var(--muted-fg); font-size: 13px; margin-top: 4px; }

.sec { padding: 40px 0 8px; border-top: 1px solid var(--border); margin-top: 40px; }
.sec:first-of-type { border-top: 0; margin-top: 8px; }
.sec .meta { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 8px; }
.sec h2 { font-size: 1.5rem; margin: 0 0 8px; letter-spacing: -0.01em; }
.sec h3 { font-size: 1.1rem; margin: 26px 0 8px; }
.sec p, .sec li { color: var(--subtle-fg); }
.sec p strong, .sec li strong { color: var(--fg); }
figure { margin: 22px 0 0; }
figure img { margin: 0 auto; border-radius: 8px; background: #fff; }
figure.bordered img { border: 1px solid var(--border); padding: 10px; }
figcaption { color: var(--muted-fg); font-size: 14px; padding-top: 10px; max-width: 900px; margin: 0 auto; }
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; align-items: start; }
@media (max-width: 860px) { .two-col { grid-template-columns: 1fr; } }

.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 14px; margin: 22px 0 6px; }
@media (max-width: 760px) { .stats { grid-template-columns: repeat(2, 1fr); } }
.stat { border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; background: var(--card-soft); }
.stat b { display: block; font-size: 1.6rem; letter-spacing: -0.02em; color: var(--fg); }
.stat span { font-size: 13px; color: var(--muted-fg); }

.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: var(--radius); margin-top: 16px; }
table { border-collapse: collapse; width: 100%; font-size: 14px; }
th, td { padding: 9px 12px; text-align: right; border-bottom: 1px solid var(--border); white-space: nowrap; }
th:first-child, td:first-child { text-align: left; }
thead th { background: var(--card-soft); font-weight: 600; color: var(--fg); }
tbody tr:last-child td { border-bottom: 0; }
td { color: var(--subtle-fg); }
td.hl { color: var(--tactile); font-weight: 700; }
.t-note { font-size: 13px; color: var(--muted-fg); margin-top: 8px; }

.cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 16px; margin-top: 18px; }
.card {
  border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; background: var(--card);
  display: flex; flex-direction: column; gap: 8px;
}
.card h3 { margin: 0; font-size: 1.05rem; }
.card p { margin: 0; font-size: 14px; }
.card .links { display: flex; gap: 8px; flex-wrap: wrap; margin-top: auto; padding-top: 6px; }
.card .links .btn { padding: 6px 12px; font-size: 13px; }
.pill { font-size: 11px; font-weight: 600; padding: 2px 8px; border-radius: 999px; background: var(--muted); color: var(--muted-fg); width: fit-content; }

pre {
  background: var(--code-bg); border-radius: 10px; padding: 14px 16px; overflow-x: auto; font-size: 13px;
  line-height: 1.55; margin: 12px 0; position: relative; color: var(--fg);
}
:not(pre) > code { background: var(--code-bg); padding: 1px 6px; border-radius: 5px; font-size: .88em; color: var(--fg); }
.copy-btn { position: absolute; top: 8px; right: 8px; padding: 4px 10px; font-size: 12px; }
.callout {
  border-left: 3px solid var(--fg); padding: 6px 14px; margin: 16px 0; color: var(--subtle-fg); background: var(--card-soft);
  border-radius: 0 8px 8px 0;
}
.formula { font-family: var(--font-mono); font-size: 15px; text-align: center; padding: 10px; color: var(--fg); }

/* ---------- authors (as on sew-mimic.com/authors) ---------- */
.people-intro { text-align: center; color: var(--muted-fg); font-size: 1.2rem; padding: 48px 0 8px; max-width: 900px; margin: 0 auto; }
.group { padding-top: 36px; }
.group h2 { border-left: 4px solid var(--fg); padding-left: 16px; margin: 0 0 20px; font-size: 1.5rem; }
.people { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 20px; }
.person { border: 1px solid var(--border); border-radius: var(--radius); background: var(--card); overflow: hidden; box-shadow: 0 1px 3px #0000000f; display: flex; flex-direction: column; }
.person .top { display: flex; gap: 14px; align-items: center; padding: 22px 18px; }
.avatar { width: 80px; height: 80px; border-radius: 50%; object-fit: cover; flex: none; border: 1px solid var(--border); background: var(--muted); }
.avatar.initials { display: inline-flex; align-items: center; justify-content: center; font-weight: 700; font-size: 1.5rem; color: var(--muted-fg); }
.person h3 { margin: 0; font-size: 1.05rem; }
.person .role { font-size: 10.5px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase; color: var(--muted-fg); margin-top: 2px; line-height: 1.35; }
.person .ext { margin-left: auto; align-self: center; color: var(--muted-fg); }
.person .ext svg { width: 18px; height: 18px; }
.person ul { margin: 0; padding: 14px 18px 18px 34px; background: var(--card-soft); flex: 1; font-size: 13.5px; color: var(--muted-fg); }
.person li + li { margin-top: 6px; }

/* ---------- viewer ---------- */
.rerun { aspect-ratio: 16 / 10; width: 100%; border: 1px solid var(--border); border-radius: var(--radius); background: #0d1117; }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--border); margin-top: 72px; }
.site-footer .inner { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; padding: 18px 24px; max-width: 1400px; margin: 0 auto; font-size: 12.5px; color: var(--muted-fg); }
.site-footer nav { display: flex; gap: 18px; flex-wrap: wrap; }
.site-footer a { text-decoration: none; }
.site-footer a:hover { text-decoration: underline; color: var(--fg); }
main:has(> .band:last-child) + .site-footer { margin-top: 0; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .carousel .track { transition: none; }
}