/* ============================================================
   NDSplat — project page styles
   ============================================================ */

:root {
  --bg:        #ffffff;
  --bg-alt:    #f6f7fb;
  --ink:       #14161c;
  --ink-soft:  #4a5061;
  --ink-faint: #8a91a3;
  --line:      #e6e8ef;
  --accent:    #6d5cf6;   /* violet */
  --accent-2:  #18b6c9;   /* teal   */
  --accent-3:  #f0566f;   /* coral (ours)*/
  --accent-ink:#5849d6;
  --ours-bg:   #f1eefe;
  --radius:    16px;
  --radius-sm: 10px;
  --maxw:      1120px;
  --shadow:    0 1px 2px rgba(20,22,28,.04), 0 8px 28px rgba(20,22,28,.06);
  --shadow-lg: 0 18px 60px rgba(20,22,28,.12);
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 76px; }

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

em { font-style: italic; }

/* ============================================================
   NAV
   ============================================================ */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  backdrop-filter: saturate(180%) blur(14px);
  background: rgba(255,255,255,.72);
  border-bottom: 1px solid transparent;
  transition: border-color .25s, background .25s, box-shadow .25s;
}
.nav.scrolled { border-bottom-color: var(--line); box-shadow: 0 2px 18px rgba(20,22,28,.05); }
.nav-inner {
  max-width: var(--maxw); margin: 0 auto; padding: 0 24px; height: 64px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-brand { display: flex; align-items: center; gap: 1px; font-weight: 800; font-size: 1.22rem; color: var(--ink); letter-spacing: -.02em; }
.nav-brand:hover { text-decoration: none; }
.brand-mark {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.brand-text { color: var(--ink); }
.nav-links { display: flex; gap: 4px; }
.nav-links a {
  color: var(--ink-soft); font-weight: 500; font-size: .92rem;
  padding: 8px 13px; border-radius: 9px; transition: background .15s, color .15s;
}
.nav-links a:hover { background: var(--bg-alt); color: var(--ink); text-decoration: none; }

.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 8px; flex-direction: column; gap: 5px; }
.nav-toggle span { width: 22px; height: 2px; background: var(--ink); border-radius: 2px; transition: .25s; }

/* ============================================================
   HERO
   ============================================================ */
.hero {
  position: relative; min-height: 100vh;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  text-align: center; overflow: hidden;
  background: radial-gradient(1200px 700px at 50% -10%, #1c1f33 0%, #0c0d17 55%, #07080f 100%);
  color: #fff; padding: 120px 24px 80px;
}
.hero-bg {
  position: absolute; inset: 0;
  background-image:
    radial-gradient(620px 420px at 16% 22%, rgba(109,92,246,.40), transparent 60%),
    radial-gradient(560px 440px at 84% 30%, rgba(24,182,201,.30), transparent 60%),
    radial-gradient(700px 480px at 60% 96%, rgba(240,86,111,.20), transparent 62%);
  filter: blur(8px);
  animation: drift 18s ease-in-out infinite alternate;
}
.hero-bg::after {
  content: ""; position: absolute; inset: 0;
  background-image: linear-gradient(rgba(255,255,255,.045) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(255,255,255,.045) 1px, transparent 1px);
  background-size: 46px 46px;
  mask-image: radial-gradient(circle at 50% 38%, #000 0%, transparent 72%);
}
@keyframes drift { from { transform: translateY(-10px) scale(1); } to { transform: translateY(14px) scale(1.05); } }

.hero-content { position: relative; z-index: 2; max-width: 880px; }
.hero-eyebrow {
  text-transform: uppercase; letter-spacing: .28em; font-size: .76rem; font-weight: 600;
  color: rgba(255,255,255,.62); margin: 0 0 22px;
}
.hero-title {
  font-size: clamp(2.4rem, 6vw, 4.6rem); font-weight: 800; line-height: 1.04;
  letter-spacing: -.03em; margin: 0 0 24px;
}
.grad {
  background: linear-gradient(100deg, #9b8cff 0%, #57d6e6 50%, #ff8aa0 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero-sub {
  font-size: clamp(1.02rem, 1.7vw, 1.24rem); color: rgba(255,255,255,.80);
  max-width: 660px; margin: 0 auto 38px; font-weight: 300; line-height: 1.6;
}
.hero-sub strong { font-weight: 600; color: #fff; }

.hero-cta { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; margin-bottom: 60px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 13px 24px; border-radius: 999px; font-weight: 600; font-size: .98rem;
  transition: transform .15s, box-shadow .2s, background .2s; cursor: pointer; border: 0;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn em { font-style: italic; }

/* Method names like "dGS"/"dBS": the italic d's slant otherwise reads as a gap
   before the upright letters. Tighten it so the d hugs the rest. */
.mname { white-space: nowrap; }
/* italic d leans right into the next glyph; a small positive gap keeps it from
   colliding with the upright G/B without reading as a word break */
.mname em { font-style: italic; margin-right: 0.06em; }
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2)); color: #fff;
  box-shadow: 0 8px 26px rgba(109,92,246,.42);
}
.btn-primary:hover { box-shadow: 0 12px 34px rgba(109,92,246,.55); }
.btn-ghost { background: rgba(255,255,255,.08); color: #fff; border: 1px solid rgba(255,255,255,.18); }
.btn-ghost:hover { background: rgba(255,255,255,.14); }

.hero-stats { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; }
.stat {
  display: flex; flex-direction: column; gap: 4px; padding: 16px 24px;
  background: rgba(255,255,255,.05); border: 1px solid rgba(255,255,255,.10);
  border-radius: var(--radius-sm); min-width: 150px;
}
.stat-num { font-size: 1.5rem; font-weight: 700; letter-spacing: -.02em; }
.stat-label { font-size: .8rem; color: rgba(255,255,255,.62); }

.scroll-hint { position: absolute; bottom: 26px; left: 50%; transform: translateX(-50%); z-index: 2; }
.scroll-hint span {
  display: block; width: 24px; height: 40px; border: 2px solid rgba(255,255,255,.4); border-radius: 14px; position: relative;
}
.scroll-hint span::before {
  content: ""; position: absolute; top: 7px; left: 50%; transform: translateX(-50%);
  width: 4px; height: 7px; background: rgba(255,255,255,.7); border-radius: 2px;
  animation: scroll 1.6s ease infinite;
}
@keyframes scroll { 0% { opacity: 0; top: 7px; } 40% { opacity: 1; } 80% { opacity: 0; top: 20px; } 100% { opacity: 0; } }

/* ============================================================
   SECTIONS
   ============================================================ */
.section { padding: 96px 0; }
.section-alt { background: var(--bg-alt); }
.section-feature { background: linear-gradient(180deg, #fbfaff 0%, #ffffff 100%); border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }

.section-head { max-width: 760px; margin: 0 auto 56px; text-align: center; }
.kicker {
  display: inline-block; text-transform: uppercase; letter-spacing: .16em; font-size: .74rem;
  font-weight: 700; color: var(--ink-faint); margin-bottom: 14px;
}
.kicker-accent { color: var(--accent-ink); }
.section-head h2 { font-size: clamp(1.9rem, 3.6vw, 2.9rem); font-weight: 800; letter-spacing: -.025em; line-height: 1.1; margin: 0 0 18px; }
.lead { font-size: 1.1rem; color: var(--ink-soft); font-weight: 300; margin: 0; line-height: 1.66; }
.lead strong { font-weight: 600; color: var(--ink); }

/* ---------- Lineage timeline ---------- */
.lineage { margin: 0 auto 64px; max-width: 920px; }
.lineage-track {
  display: flex; align-items: stretch; justify-content: center; gap: 8px; flex-wrap: wrap;
}
.node {
  display: flex; flex-direction: column; gap: 3px; padding: 18px 22px;
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius-sm);
  min-width: 134px; text-align: center; color: var(--ink); box-shadow: var(--shadow);
  transition: transform .18s, box-shadow .2s, border-color .2s;
}
.node:hover { text-decoration: none; transform: translateY(-4px); box-shadow: var(--shadow-lg); border-color: var(--accent); }
.node-year { font-size: .72rem; font-weight: 600; color: var(--ink-faint); text-transform: uppercase; letter-spacing: .08em; }
.node-name { font-size: 1.32rem; font-weight: 800; letter-spacing: -.02em; }
.node-desc { font-size: .82rem; color: var(--ink-soft); }
.node-accent {
  background: linear-gradient(135deg, var(--accent), var(--accent-2)); border-color: transparent; color: #fff;
}
.node-accent .node-year, .node-accent .node-desc { color: rgba(255,255,255,.85); }
.node-accent:hover { border-color: transparent; }
.node-arrow { display: flex; align-items: center; color: var(--ink-faint); font-size: 1.3rem; font-weight: 300; }

/* ---------- Render-FM branch (application off the main track) ---------- */
.lineage-branch {
  display: flex; align-items: center; justify-content: center; gap: 22px;
  margin: 0 auto; max-width: 660px; position: relative; padding-top: 30px;
}
.branch-connector {
  position: absolute; top: 0; left: 50%; width: 2px; height: 30px;
  background: linear-gradient(var(--line), var(--accent-2)); border-radius: 2px;
}
.node-branch {
  position: relative; min-width: 200px; border-style: dashed; border-color: var(--accent-2);
  background: linear-gradient(180deg, #ffffff, #f3fdff);
}
.node-branch:hover { border-color: var(--accent-2); border-style: solid; }
.node-branch .node-desc { line-height: 1.35; }
.node-badge {
  position: absolute; top: -10px; left: 50%; transform: translateX(-50%);
  background: var(--accent-2); color: #04222a; font-size: .62rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: .08em; padding: 3px 10px; border-radius: 999px;
  white-space: nowrap;
}
.branch-note { margin: 0; font-size: .92rem; color: var(--ink-soft); text-align: left; max-width: 320px; }
.branch-note strong { color: var(--ink); font-weight: 600; }

/* ---------- Axes cards ---------- */
.axes { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.axis-card {
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 30px 26px; box-shadow: var(--shadow); transition: transform .18s, box-shadow .2s;
}
.axis-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.axis-icon {
  width: 50px; height: 50px; display: grid; place-items: center; font-size: 1.5rem;
  border-radius: 13px; margin-bottom: 18px;
  background: linear-gradient(135deg, rgba(109,92,246,.12), rgba(24,182,201,.12)); color: var(--accent-ink);
}
.axis-card h3 { margin: 0 0 10px; font-size: 1.18rem; font-weight: 700; letter-spacing: -.01em; }
.axis-card p { margin: 0; color: var(--ink-soft); font-size: .96rem; }

/* ============================================================
   FEATURE (dGS/dBS)
   ============================================================ */
.section-feature .authors { font-size: 1.04rem; color: var(--ink-soft); margin: 8px 0 0; font-weight: 500; }
.section-feature .authors em { font-weight: 700; color: var(--accent-ink); }

.feature-grid { display: grid; grid-template-columns: 1.55fr 1fr; gap: 40px; align-items: start; margin-bottom: 56px; }
.feature-text p { color: var(--ink-soft); margin: 0 0 18px; }
.feature-text p:last-child { margin-bottom: 0; }
.feature-text strong { color: var(--ink); font-weight: 600; }
.feature-text .lead { font-size: 1.08rem; color: var(--ink); }

.feature-side { position: sticky; top: 90px; }
.highlight-card {
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px; box-shadow: var(--shadow);
}
.highlight-card h4 { margin: 0 0 16px; font-size: .82rem; text-transform: uppercase; letter-spacing: .12em; color: var(--ink-faint); }
.check-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 13px; }
.check-list li { font-size: .96rem; color: var(--ink-soft); padding-left: 26px; position: relative; }
.check-list li::before {
  content: "✓"; position: absolute; left: 0; top: 1px; color: var(--accent-2); font-weight: 700;
}
.check-list span { font-weight: 700; color: var(--ink); }

/* ---------- Equations ---------- */
.eq-block {
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 30px; margin-bottom: 60px; box-shadow: var(--shadow);
}
.eq-label { margin: 0 0 18px; color: var(--ink-soft); font-size: .96rem; }
.eq-label em { font-family: var(--mono); font-style: normal; color: var(--ink); }
.eq-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-bottom: 18px; }
.eq {
  background: var(--bg-alt); border: 1px solid var(--line); border-radius: var(--radius-sm);
  padding: 18px 20px; position: relative;
}
.eq-tag {
  display: inline-block; font-size: .68rem; text-transform: uppercase; letter-spacing: .1em;
  font-weight: 700; color: var(--accent-ink); margin-bottom: 10px;
}
.eq code { display: block; font-family: var(--mono); font-size: 1.02rem; color: var(--ink); }
.eq-note { margin: 0; font-size: .9rem; color: var(--ink-soft); line-height: 1.6; }
.eq-note strong { color: var(--ink); }
.eq-note code { font-family: var(--mono); background: var(--bg-alt); padding: 1px 6px; border-radius: 5px; font-size: .85rem; }

/* ============================================================
   DATA TABLE
   ============================================================ */
.table-title { font-size: 1.36rem; font-weight: 700; letter-spacing: -.01em; margin: 0 0 8px; text-align: center; }
.table-cap { text-align: center; max-width: 820px; margin: 0 auto 26px; color: var(--ink-soft); font-size: .94rem; }
.table-cap em { font-style: italic; }

.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); background: var(--bg); }
.data-table { width: 100%; border-collapse: collapse; font-size: .9rem; min-width: 720px;
  /* tabular figures so bold and regular numbers share a fixed digit width and
     stay vertically aligned within centered/right-aligned columns */
  font-variant-numeric: tabular-nums; font-feature-settings: "tnum" 1; }
.data-table thead th {
  background: #11131e; color: #fff; font-weight: 600; padding: 14px 12px; text-align: right;
  white-space: nowrap; font-size: .82rem; position: sticky; top: 0;
}
.data-table thead th:first-child, .data-table thead th:nth-child(2) { text-align: left; }
.data-table tbody td { padding: 11px 12px; text-align: right; border-top: 1px solid var(--line); white-space: nowrap; color: var(--ink-soft); }
/* Body alignment is class-based, not nth-child: the rowspan'd Dataset cell
   shifts cell positions in non-leading rows, so positional rules misfire. */
.data-table tbody td:first-child { text-align: left; font-weight: 600; color: var(--ink); vertical-align: middle; }
.data-table tbody td.c-method { text-align: left; color: var(--ink); }
.data-table tbody td.c-gauss { text-align: right; }
.data-table tbody tr.grp td { border-top: 2px solid var(--line); }
.data-table tbody tr.dash td:not(:first-child) { border-top: 1px dashed var(--line); }
.data-table tbody tr.ours { background: var(--ours-bg); }
.data-table tbody tr.ours td { color: var(--ink); }
.data-table tbody tr.ours td:nth-child(2) { font-weight: 700; color: var(--accent-ink); }
.data-table b { color: var(--ink); font-weight: 700; }
.data-table tr.ours b { color: var(--accent-ink); }
.dyn-tag {
  display: inline-block; margin-left: 8px; font-size: .62rem; text-transform: uppercase; letter-spacing: .08em;
  font-weight: 700; color: var(--accent-2); background: rgba(24,182,201,.12); padding: 2px 7px; border-radius: 999px;
  vertical-align: middle;
}
.table-foot { text-align: center; font-size: .85rem; color: var(--ink-faint); margin: 18px 0 0; }

/* ---------- SOTA comparison table ---------- */
.sota-table { min-width: 760px; }
.sota-table thead th { text-align: center; }
.sota-table thead th:first-child, .sota-table thead th:nth-child(2) { text-align: left; }
.sota-table thead tr.grp-head th { font-size: .76rem; letter-spacing: .04em; }
.sota-table tbody td { text-align: center; }
.sota-table tbody td.c-type { text-align: center; font-weight: 700; color: var(--ink-faint);
  text-transform: uppercase; letter-spacing: .06em; font-size: .68rem; border-right: 1px solid var(--line); }
.sota-table tbody td.c-name { text-align: left; color: var(--ink); }
.sota-table tbody td.sep { border-left: 1px solid var(--line); }
.sota-table tbody tr.ours { background: var(--ours-bg); }
.sota-table tbody tr.ours td.c-name { font-weight: 700; color: var(--accent-ink); }
.sota-table tbody tr.grp td { border-top: 2px solid var(--line); }
/* rank highlights: best = accent fill, second = soft accent */
.sota-table td.best { background: rgba(109,92,246,.16); color: var(--accent-ink); font-weight: 800; border-radius: 6px; }
.sota-table td.second { background: rgba(24,182,201,.14); color: #0d8090; font-weight: 700; }
.sota-legend { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; margin: 14px 0 0; font-size: .82rem; color: var(--ink-faint); }
.sota-legend span { display: inline-flex; align-items: center; gap: 7px; }
.sota-legend i { width: 14px; height: 14px; border-radius: 4px; display: inline-block; }
.sota-legend i.best { background: rgba(109,92,246,.16); }
.sota-legend i.second { background: rgba(24,182,201,.14); }

/* ============================================================
   PAPER CARDS
   ============================================================ */
.paper {
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 36px; box-shadow: var(--shadow); max-width: 820px; margin: 0 auto;
  transition: box-shadow .2s;
}
.paper:hover { box-shadow: var(--shadow-lg); }
.paper-wide { max-width: 900px; }
.paper-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 26px; align-items: start; }
.paper-pair .paper { max-width: none; margin: 0; }

.paper-meta { margin-bottom: 18px; }
.venue {
  display: inline-block; font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .08em;
  padding: 5px 12px; border-radius: 999px; margin-bottom: 14px;
}
.venue-iclr { background: rgba(109,92,246,.12); color: var(--accent-ink); }
.venue-iccv { background: rgba(24,182,201,.14); color: #0d8090; }
.venue-eccv { background: rgba(240,86,111,.13); color: #cf3b54; }
.paper-title { font-size: 1.34rem; font-weight: 700; letter-spacing: -.015em; line-height: 1.28; margin: 0 0 10px; }
.paper-pair .paper-title { font-size: 1.18rem; }
.paper-authors { font-size: .9rem; color: var(--ink-faint); margin: 0; line-height: 1.5; }
.paper-abstract { color: var(--ink-soft); margin: 0 0 22px; font-size: .98rem; }
.paper-abstract strong { color: var(--ink); font-weight: 600; }

.paper-links { display: flex; gap: 10px; flex-wrap: wrap; }
.link-chip {
  display: inline-flex; align-items: center; gap: 6px; padding: 8px 16px; border-radius: 999px;
  background: var(--bg-alt); border: 1px solid var(--line); color: var(--ink); font-weight: 500; font-size: .88rem;
  transition: background .15s, border-color .15s, transform .15s;
}
.link-chip:hover { text-decoration: none; background: #fff; border-color: var(--accent); transform: translateY(-2px); color: var(--accent-ink); }

/* ============================================================
   BIBTEX
   ============================================================ */
.bib-wrap { position: relative; max-width: 920px; margin: 0 auto; }
.copy-btn {
  position: absolute; top: 14px; right: 14px; z-index: 2;
  background: rgba(255,255,255,.10); color: #cdd2e4; border: 1px solid rgba(255,255,255,.18);
  padding: 7px 15px; border-radius: 8px; font-size: .82rem; font-weight: 600; cursor: pointer;
  transition: background .15s, color .15s; font-family: var(--font);
}
.copy-btn:hover { background: rgba(255,255,255,.20); color: #fff; }
.copy-btn.copied { background: var(--accent-2); border-color: var(--accent-2); color: #04222a; }
.bib-wrap pre {
  background: #0e1019; border: 1px solid #1f2336; border-radius: var(--radius);
  padding: 28px 26px; overflow-x: auto; margin: 0;
}
.bib-wrap code { font-family: var(--mono); font-size: .82rem; color: #c8cde0; line-height: 1.7; white-space: pre; }

/* ============================================================
   FOOTER
   ============================================================ */
.footer { background: #0c0d17; color: #aab0c4; padding: 56px 0; }
.footer-inner { display: flex; flex-direction: column; align-items: center; text-align: center; gap: 16px; }
.footer-brand { font-weight: 800; font-size: 1.4rem; }
.footer-brand .brand-text { color: #fff; }
.footer-note { max-width: 540px; margin: 0; font-size: .92rem; color: #8389a0; font-weight: 300; }
.footer-links { display: flex; gap: 22px; }
.footer-links a { color: #cdd2e4; font-weight: 500; font-size: .92rem; }
.footer-links a:hover { color: #fff; }

/* ============================================================
   REVEAL ANIMATION
   ============================================================ */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .7s ease, transform .7s ease; }
.reveal.in { opacity: 1; transform: none; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 920px) {
  .feature-grid { grid-template-columns: 1fr; }
  .feature-side { position: static; }
  .axes { grid-template-columns: 1fr; }
  .paper-pair { grid-template-columns: 1fr; }
  .eq-row { grid-template-columns: 1fr; }
}

@media (max-width: 720px) {
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; flex-direction: column; position: absolute; top: 64px; left: 0; right: 0;
    background: rgba(255,255,255,.98); border-bottom: 1px solid var(--line); padding: 12px;
    backdrop-filter: blur(14px); gap: 2px;
  }
  .nav-links.open a { padding: 12px 16px; }
  .nav-toggle { display: flex; }
  .section { padding: 68px 0; }
  .node-arrow { transform: rotate(90deg); }
  .lineage-track { flex-direction: column; align-items: center; }
  .node { width: 100%; max-width: 280px; }
  .lineage-branch { flex-direction: column; gap: 16px; max-width: 280px; }
  .branch-note { text-align: center; }
  .paper { padding: 26px; }
  .hero-stats .stat { min-width: 130px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; }
}