/* Belt-Finger project page. Plain academic style: one centred column, white background. */

:root {
  --text: #222;
  --muted: #666;
  --faint: #8a8a8a;
  --line: #e4e4e4;
  --bg-soft: #f6f6f6;
  --link: #2563c9;
  --btn: #363636;
  --btn-hover: #111;
  --btn-off: #b5b5b5;
  --badge-v1: #e8f0fb;
  --badge-v1-text: #1f4f99;
  --badge-v2: #e7f5ef;
  --badge-v2-text: #17684a;
  --v1-accent: #2f6fcf;
  --v1-band: #f0f5fc;
  --v1-band-line: #d9e5f6;
  --v2-accent: #1f8a5f;
  --v2-band: #eef7f2;
  --v2-band-line: #d3eadd;
  --col: 960px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: #fff;
  color: var(--text);
  font-family: "Noto Sans", -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16.5px;
  line-height: 1.6;
}

a { color: var(--link); text-decoration: none; }
a:hover { text-decoration: underline; }

img, video { max-width: 100%; display: block; }

.container { max-width: var(--col); margin: 0 auto; padding: 0 16px; }

/* ---------- top nav ---------- */
.topnav {
  position: sticky; top: 0; z-index: 10;
  background: rgba(255, 255, 255, .96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: saturate(1.2) blur(6px);
}
.topnav .container {
  display: flex; gap: 22px; align-items: center;
  height: 48px; overflow-x: auto; white-space: nowrap;
  scrollbar-width: none;
}
.topnav .container::-webkit-scrollbar { display: none; }
.topnav .brand { font-weight: 700; color: var(--text); margin-right: auto; }
.topnav a:not(.brand) { color: var(--muted); font-size: 15px; }
.topnav a:not(.brand):hover { color: var(--text); text-decoration: none; }

section[id] { scroll-margin-top: 60px; }

/* ---------- hero ---------- */
.hero { text-align: center; padding: 56px 0 8px; }
.hero h1 {
  font-size: 44px; line-height: 1.15; font-weight: 700;
  margin: 0 0 10px; letter-spacing: -.5px;
}
.hero .subtitle {
  font-size: 22px; line-height: 1.35; color: #444; font-weight: 500;
  margin: 0 auto 4px; max-width: 760px;
}
.authors { font-size: 18px; margin: 0 0 4px; }
.authors span { white-space: nowrap; margin: 0 7px; }
.affil { color: var(--muted); font-size: 14.5px; margin: 0; }
.affil span { white-space: nowrap; margin: 0 6px; }
sup { font-size: .7em; }

/* ---------- section headings ---------- */
.section { padding-top: 40px; padding-bottom: 8px; }
.section + .section { border-top: 1px solid var(--line); }
h2 {
  font-size: 30px; font-weight: 700; text-align: center;
  margin: 0 0 18px;
}
h3 { font-size: 20px; font-weight: 600; margin: 0 0 8px; }

/* ---------- paper sections: full-width tinted header band ---------- */
.paper { margin-top: 64px; scroll-margin-top: 48px; }
.paper.v1 { --accent: var(--v1-accent); --band: var(--v1-band); --band-line: var(--v1-band-line); }
.paper.v2 { --accent: var(--v2-accent); --band: var(--v2-band); --band-line: var(--v2-band-line); }
.paper-band {
  background: var(--band);
  border-top: 6px solid var(--accent);
  border-bottom: 1px solid var(--band-line);
  padding: 38px 0 34px;
}
.paper-band .badge { background: #fff; box-shadow: 0 0 0 1px var(--band-line); }
.paper-body { padding-top: 32px; }

.paper-head { text-align: center; }
.paper-head .kicker {
  display: inline-block;
  font-size: 13px; letter-spacing: .12em; text-transform: uppercase;
  color: #fff; background: var(--accent); font-weight: 700;
  padding: 3px 12px; border-radius: 4px; margin: 0 0 12px;
}
.paper-head h2 { margin-bottom: 6px; }
.paper-head .paper-title { font-size: 19px; color: #444; margin: 0 auto 12px; max-width: 780px; }
.paper-head .authors { font-size: 16.5px; }

.badge {
  display: inline-block; font-size: 13.5px; font-weight: 600;
  padding: 3px 12px; border-radius: 999px; margin: 8px 0 4px;
}
.badge.v1 { background: var(--badge-v1); color: var(--badge-v1-text); }
.badge.v2 { background: var(--badge-v2); color: var(--badge-v2-text); }

/* ---------- link buttons ---------- */
.links { display: flex; flex-wrap: wrap; justify-content: center; gap: 8px; margin: 14px 0 0; }
.btn {
  display: inline-flex; align-items: center; gap: 7px;
  background: var(--btn); color: #fff;
  padding: 7px 16px; border-radius: 999px;
  font-size: 15px; font-weight: 500; line-height: 1.3;
}
.btn:hover { background: var(--btn-hover); text-decoration: none; }
.btn i { font-size: 15px; }
.btn.off { background: var(--btn-off); cursor: default; }
.btn.off:hover { background: var(--btn-off); }
.btn .soon { font-size: 12px; opacity: .9; font-weight: 400; }

/* ---------- text ---------- */
.prose { max-width: 820px; margin: 0 auto; }
.prose p { margin: 0 0 14px; text-align: justify; hyphens: auto; }

/* ---------- overview cards ---------- */
.cards { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; margin: 26px 0 8px; }
.card {
  border: 1px solid var(--line); border-radius: 10px; overflow: hidden;
  display: flex; flex-direction: column; color: inherit;
}
.card.v1 { border-top: 5px solid var(--v1-accent); }
.card.v2 { border-top: 5px solid var(--v2-accent); }
.card:hover { box-shadow: 0 2px 10px rgba(0, 0, 0, .08); text-decoration: none; }
.card .thumb {
  background: #fff; aspect-ratio: 2.3 / 1; min-height: 0;
  padding: 10px 8px; border-bottom: 1px solid var(--line);
}
.card .thumb img { width: 100%; height: 100%; object-fit: contain; }
.card .body { padding: 14px 18px 16px; }
.card h3 { margin: 0 0 2px; }
.card .badge { margin: 2px 0 8px; }
.card p { margin: 0; color: #444; font-size: 15.5px; }
.card .more { display: inline-block; margin-top: 8px; color: var(--link); font-size: 15px; }

/* ---------- videos ---------- */
.video-block { margin: 34px 0 0; }
.video-block .vhead { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; margin-bottom: 8px; }
.video-block .vhead h3 { margin: 0; }
.video-block .dur { color: var(--faint); font-size: 14px; font-variant-numeric: tabular-nums; }
.video-block video {
  width: 100%; height: auto; border-radius: 8px;
}
.video-block.narrow video { max-width: 720px; margin: 0 auto; }
.video-block.narrow-sm video { max-width: 600px; margin: 0 auto; }
.caption { color: #444; font-size: 15.5px; margin: 10px 0 0; }
.caption .ref { color: var(--faint); font-size: 13.5px; white-space: nowrap; }

/* ---------- tables ---------- */
.table-wrap { overflow-x: auto; margin: 12px 0 0; }
table { border-collapse: collapse; margin: 0 auto; font-size: 15px; min-width: 60%; }
th, td { padding: 6px 14px; text-align: center; border-bottom: 1px solid var(--line); }
th { font-weight: 600; border-bottom: 2px solid #cfcfcf; }
td:first-child, th:first-child { text-align: left; }
td.best { font-weight: 700; }
.table-note { text-align: center; color: var(--faint); font-size: 13.5px; margin: 6px 0 0; }

.resources table { width: 100%; background: #fff; border: 1px solid var(--line); }
.resources td, .resources th { text-align: left; padding: 10px 14px; }
.resources .muted { color: var(--faint); }
.resources th:first-child { width: 24%; }
.resources th:not(:first-child) { width: 38%; }

/* ---------- bibtex ---------- */
.bib { position: relative; margin: 0 0 18px; }
.bib h3 { font-size: 16px; color: var(--muted); font-weight: 600; }
/* shared resources + bibtex on a neutral band */
.shared { background: var(--bg-soft); border-top: 1px solid var(--line); margin-top: 64px; padding-bottom: 24px; }
.shared .section + .section { border-top-color: #e2e2e2; }

.bib pre {
  background: #fff; border: 1px solid var(--line); border-radius: 8px;
  padding: 14px 16px; margin: 0; overflow-x: auto;
  font-size: 13.5px; line-height: 1.5;
}
.copy {
  position: absolute; top: 34px; right: 8px;
  border: 1px solid var(--line); background: #fff; color: var(--muted);
  border-radius: 6px; padding: 3px 10px; font: inherit; font-size: 13px; cursor: pointer;
}
.copy:hover { color: var(--text); border-color: #bbb; }

/* ---------- footer ---------- */
footer {
  border-top: 1px solid var(--line); padding: 26px 0 40px;
  color: var(--faint); font-size: 14px; text-align: center;
}
footer p { margin: 0 0 6px; }

/* ---------- small screens ---------- */
@media (max-width: 760px) {
  body { font-size: 16px; }
  .hero { padding-top: 36px; }
  .hero h1 { font-size: 34px; }
  .hero .subtitle { font-size: 18px; }
  h2 { font-size: 25px; }
  .cards { grid-template-columns: 1fr; }
  .prose p { text-align: left; }
  .topnav .container { gap: 16px; }
  .copy { top: 30px; }
  table { font-size: 14px; }
  th, td { padding: 6px 8px; }
  .resources td, .resources th { padding: 8px 6px; }
  .resources td a { overflow-wrap: anywhere; }
}