/* ===================== Tokens ===================== */
:root{
  --bg:#ffffff;
  --bg-alt:#f7f8fa;
  --fg:#15181d;
  --muted:#667085;
  --border:#e6e8ec;
  --accent:#2563eb;
  --accent-soft:#eaf0fe;
  --maxw:1120px;
  --narrow:760px;
  --nav-h:58px;
  --radius:14px;
  --shadow:0 1px 2px rgba(16,24,40,.05), 0 8px 28px rgba(16,24,40,.06);
  --font:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,Helvetica,Arial,sans-serif;
  --mono:'JetBrains Mono',ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;font-family:var(--font);color:var(--fg);background:var(--bg);
  font-size:17px;line-height:1.65;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3{line-height:1.2;letter-spacing:-.02em;font-weight:700}
img{max-width:100%;height:auto;display:block}

.container{max-width:var(--maxw);margin:0 auto;padding:0 24px}
.container.narrow{max-width:var(--narrow)}

/* ===================== Nav ===================== */
.nav{
  position:sticky;top:0;z-index:50;height:var(--nav-h);
  background:rgba(255,255,255,.82);backdrop-filter:saturate(180%) blur(12px);
  border-bottom:1px solid var(--border);
}
.nav-inner{max-width:var(--maxw);margin:0 auto;padding:0 24px;height:var(--nav-h);
  display:flex;align-items:center;justify-content:space-between}
.nav-brand{font-weight:800;font-size:1.15rem;color:var(--fg);letter-spacing:-.03em}
.nav-brand:hover{text-decoration:none}
.nav-links{list-style:none;display:flex;gap:28px;margin:0;padding:0}
.nav-links a{color:var(--muted);font-weight:500;font-size:.95rem}
.nav-links a:hover,.nav-links a.active{color:var(--fg);text-decoration:none}
.nav-toggle{display:none;background:none;border:0;font-size:1.25rem;color:var(--fg);cursor:pointer}

/* ===================== Hero ===================== */
.hero{padding:64px 0 40px;text-align:center}
.venue{display:block;font-weight:800;font-size:clamp(1.6rem,3.4vw,2.1rem);letter-spacing:.04em;text-transform:uppercase;
  color:var(--accent);margin:12px 0 20px}
.authors a{color:var(--accent)}
.authors a:hover{text-decoration:underline}
.title{margin:0 auto 20px;max-width:940px}
.brand{display:block;font-weight:800;font-size:clamp(2.7rem,6.6vw,4.3rem);line-height:1.02;letter-spacing:-.035em;
  background:linear-gradient(96deg,#15181d 0%,#15181d 50%,#14a6bc 72%,#2f7ff0 100%);
  -webkit-background-clip:text;background-clip:text;-webkit-text-fill-color:transparent;color:transparent}
.subtitle{display:block;margin-top:.3em;font-weight:600;font-size:clamp(1.25rem,2.7vw,1.9rem);
  line-height:1.18;letter-spacing:-.02em;color:var(--fg)}
.authors{list-style:none;display:flex;flex-wrap:wrap;justify-content:center;gap:6px 20px;margin:0 0 6px;padding:0;font-size:1.08rem;font-weight:500}
.affil{color:var(--muted);margin:0 0 26px}
.buttons{display:flex;flex-wrap:wrap;justify-content:center;gap:12px}
.btn{display:inline-flex;align-items:center;gap:8px;padding:10px 18px;border-radius:999px;
  font-weight:600;font-size:.95rem;border:1px solid var(--border);background:#fff;color:var(--fg);transition:.15s}
.btn:hover{text-decoration:none;transform:translateY(-1px);box-shadow:var(--shadow)}
.btn-primary{background:var(--fg);color:#fff;border-color:var(--fg)}
.btn-primary:hover{background:#000}
.btn-disabled{color:var(--muted);background:var(--bg-alt);cursor:default;pointer-events:none;opacity:.85}
.btn .soon{font-weight:500;opacity:.7;font-size:.85em}

/* ===================== Sections ===================== */
.section{padding:64px 0}
.section.section-tight{padding:24px 0 8px}
.section.alt{background:var(--bg-alt);border-top:1px solid var(--border);border-bottom:1px solid var(--border)}
.section h2{font-size:1.9rem;text-align:center;margin:0 0 8px}
.section h3.sub{font-size:1.15rem;margin:32px 0 6px}
section[id]{scroll-margin-top:calc(var(--nav-h) + 12px)}
.lead{color:var(--muted);text-align:center;max-width:760px;margin:6px auto 28px}
.lead.small{font-size:.92rem;margin-bottom:18px}
.subhead{text-align:center;font-size:1.3rem;font-weight:700;letter-spacing:-.01em;margin:42px 0 20px}
.lead + .subhead{margin-top:6px}
.prose{max-width:var(--narrow);margin:24px auto 0}
.keywords{list-style:none;display:flex;flex-wrap:wrap;gap:10px;justify-content:center;padding:0;margin:24px 0 0}
.keywords li{font-size:.85rem;color:var(--muted);background:var(--bg-alt);border:1px solid var(--border);
  padding:5px 12px;border-radius:999px}

/* ===================== Figures ===================== */
.fig{margin:0 auto;text-align:center}
.fig img{margin:0 auto;border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow)}
.fig figcaption,.video-card figcaption{color:var(--muted);font-size:.9rem;margin-top:12px;max-width:820px;
  margin-left:auto;margin-right:auto;text-align:center}

/* ===================== Video embed (YouTube) ===================== */
.video-embed{position:relative;width:100%;aspect-ratio:16/9;border-radius:var(--radius);overflow:hidden;
  box-shadow:var(--shadow);background:#000}
.video-embed iframe{position:absolute;inset:0;width:100%;height:100%;border:0}

/* ===================== Tabs ===================== */
.tabs{margin-top:8px}
.tab-btns{display:flex;justify-content:center;gap:8px;flex-wrap:wrap;margin-bottom:28px}
.tab-btn{padding:9px 20px;border-radius:999px;border:1px solid var(--border);background:#fff;color:var(--muted);
  font-weight:600;font-size:.95rem;cursor:pointer;transition:.15s;font-family:inherit}
.tab-btn:hover{color:var(--fg)}
.tab-btn.active{background:var(--fg);color:#fff;border-color:var(--fg)}
.tab-panel{display:none}
.tab-panel.active{display:block;animation:fade .25s ease}
@keyframes fade{from{opacity:0;transform:translateY(4px)}to{opacity:1;transform:none}}

/* ===================== Video gallery ===================== */
.video-grid{display:flex;flex-direction:column;gap:28px;max-width:980px;margin:0 auto}
.video-card{margin:0}
.video-card video{width:100%;height:auto;display:block;border:1px solid var(--border);border-radius:var(--radius);
  background:#000;box-shadow:var(--shadow);object-fit:contain}
.v-tc{aspect-ratio:6144/1228}
.v-n3{aspect-ratio:4056/1094}
.v-nd{aspect-ratio:1920/330}
.v-seg{aspect-ratio:2028/546}

/* ===================== Tables ===================== */
.table-wrap{max-width:720px;margin:40px auto 0;overflow-x:auto}
table{width:100%;border-collapse:collapse;font-size:.95rem}
table caption{caption-side:bottom;color:var(--muted);font-size:.85rem;margin-top:12px;text-align:center}
th,td{padding:10px 14px;text-align:right;border-bottom:1px solid var(--border);white-space:nowrap}
th:first-child,td:first-child{text-align:left}
thead th{font-weight:600;color:var(--muted);border-bottom:2px solid var(--border)}
tbody tr.ours{background:var(--accent-soft)}
tbody tr.ours td{border-bottom-color:#c9d9fb}
tbody tr.ours td:first-child{font-weight:700;border-left:3px solid var(--accent)}

/* ===================== Code / BibTeX ===================== */
.code-block{position:relative;background:var(--bg-alt);border:1px solid var(--border);border-radius:var(--radius);margin-top:8px}
.code-block pre{margin:0;padding:22px;overflow-x:auto}
.code-block code{font-family:var(--mono);font-size:.85rem;line-height:1.6;color:#1f2430}
.copy-btn{position:absolute;top:12px;right:12px;display:inline-flex;align-items:center;gap:6px;
  padding:6px 12px;font-size:.82rem;font-weight:600;font-family:inherit;color:var(--fg);
  background:#fff;border:1px solid var(--border);border-radius:8px;cursor:pointer;transition:.15s}
.copy-btn:hover{box-shadow:var(--shadow)}
.copy-btn.copied{color:#fff;background:var(--accent);border-color:var(--accent)}
.code-block-empty .bibtex-soon{margin:0;padding:30px 22px;text-align:center;color:var(--muted);font-size:.95rem}
.code-block-empty .soon{opacity:.75}

/* ===================== Related links ===================== */
.related-list{list-style:none;padding:0;margin:24px 0 0;display:flex;flex-direction:column;gap:14px}
.related-item{background:#fff;border:1px solid var(--border);border-radius:12px;padding:16px 20px}
.related-title{font-weight:700;font-size:1rem;color:var(--fg);line-height:1.35}
.related-title:hover{color:var(--accent)}
.related-meta{margin:6px 0 0;color:var(--muted);font-size:.9rem;display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.related-venue{color:var(--muted);font-size:.74rem;font-weight:600;background:var(--bg-alt);
  border:1px solid var(--border);padding:2px 9px;border-radius:999px;white-space:nowrap}

/* ===================== Footer ===================== */
.footer{padding:48px 0;border-top:1px solid var(--border);text-align:center}
.footer p{margin:4px 0}
.footer .muted,.muted{color:var(--muted);font-size:.88rem}

/* ===================== Responsive ===================== */
@media (max-width:720px){
  body{font-size:16px}
  .nav-toggle{display:block}
  .nav-links{position:absolute;top:var(--nav-h);left:0;right:0;flex-direction:column;gap:0;
    background:#fff;border-bottom:1px solid var(--border);padding:8px 0;display:none}
  .nav-links.open{display:flex}
  .nav-links li{width:100%}
  .nav-links a{display:block;padding:12px 24px}
  .hero{padding:44px 0 32px}
  .section{padding:48px 0}
}