@import url("https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@500;600;700&family=IBM+Plex+Mono:wght@400;500;600&family=Source+Serif+4:opsz,wght@8..60,400;8..60,500;8..60,600&display=swap");

:root {
  --bg: #fbfbf8;
  --bg-alt: #f2f4f1;
  --text: #10151a;
  --text-muted: #59625f;
  --border: #dfe4e0;
  --accent: #0f6e64;
  --accent-strong: #0a4d46;
  --accent-bright: #17b8a4;
  --accent-soft: #e4f0ed;
  --warm: #c9501f;
  --warm-strong: #983b16;
  --warm-soft: #f8e7dd;
  --code-bg: #eef1ee;
  --shadow: 0 1px 3px rgba(15,25,20,0.07), 0 1px 2px rgba(15,25,20,0.05);
  --max-w: 980px;
  --font-display: "Space Grotesk", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", "SF Mono", ui-monospace, Menlo, Consolas, monospace;
  --font-serif: "Source Serif 4", Georgia, "Times New Roman", serif;
}

:root[data-theme="dark"] {
  --bg: #0b0f0e;
  --bg-alt: #121816;
  --text: #e9eeec;
  --text-muted: #94a19c;
  --border: #24302b;
  --accent: #23c4af;
  --accent-strong: #6fe0cf;
  --accent-bright: #23c4af;
  --accent-soft: #132723;
  --warm: #e8794a;
  --warm-strong: #f4a17a;
  --warm-soft: #2a1b13;
  --code-bg: #16201c;
  --shadow: 0 1px 3px rgba(0,0,0,0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0b0f0e;
    --bg-alt: #121816;
    --text: #e9eeec;
    --text-muted: #94a19c;
    --border: #24302b;
    --accent: #23c4af;
    --accent-strong: #6fe0cf;
    --accent-bright: #23c4af;
    --accent-soft: #132723;
    --warm: #e8794a;
    --warm-strong: #f4a17a;
    --warm-soft: #2a1b13;
    --code-bg: #16201c;
    --shadow: 0 1px 3px rgba(0,0,0,0.4);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Source Sans Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

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

/* ---------- Top nav ---------- */

.topnav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.topnav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 52px;
}

.topnav-brand {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.08rem;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.01em;
}
.topnav-brand .psi { color: var(--accent); }

.topnav-links {
  display: flex;
  gap: 22px;
}
.topnav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.86rem;
  font-weight: 600;
  transition: color 0.12s ease;
}
.topnav-links a:hover { color: var(--accent-strong); }

@media (max-width: 560px) {
  .topnav-links { gap: 14px; }
  .topnav-links a { font-size: 0.78rem; }
}

/* ---------- Header / Hero ---------- */

header.hero {
  position: relative;
  padding: 56px 0 36px;
  text-align: center;
  border-bottom: 1px solid var(--border);
  background: linear-gradient(180deg, var(--accent-soft), var(--bg) 70%);
  scroll-margin-top: 52px;
  overflow: hidden;
}


.hero-wavelets {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  fill: none;
  stroke: var(--accent);
  stroke-width: 1.4;
  opacity: 0.16;
  pointer-events: none;
}
:root[data-theme="dark"] .hero-wavelets { opacity: 0.22; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .hero-wavelets { opacity: 0.22; }
}
header.hero .wrap { position: relative; }


h1.title {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  line-height: 1.25;
  margin: 0 auto 20px;
  max-width: 840px;
  font-weight: 600;
  letter-spacing: -0.015em;
}

h1.title .psi { color: var(--accent); }

.psi-icon {
  height: 0.72em;
  width: auto;
  vertical-align: -0.02em;
  fill: currentColor;
  display: inline-block;
}
.psi-accent { fill: var(--accent); }

/* the glyph is a single fixed-weight vector path (no font-weight axis), so
   approximate bold by fattening it with a matching stroke in bold contexts */
b .psi-icon, strong .psi-icon,
h1 .psi-icon, h2 .psi-icon, h3 .psi-icon,
.topnav-brand .psi-icon,
.compare-label .psi-icon,
.vlm-cot-label .psi-icon {
  stroke: currentColor;
  stroke-width: 0.4px;
  paint-order: stroke fill;
}

h1.title .psi-icon,
.topnav-brand .psi-icon {
  stroke-width: 0.55px;
}

p.subtitle {
  font-size: clamp(1.05rem, 2vw, 1.3rem);
  color: var(--text-muted);
  max-width: 760px;
  margin: 0 auto 20px;
  font-weight: 400;
}

.authors {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 28px;
}

.badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
  margin-bottom: 8px;
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 9px 18px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 600;
  box-shadow: var(--shadow);
  transition: transform 0.12s ease, border-color 0.12s ease;
}

.badge:hover { transform: translateY(-1px); border-color: var(--accent); color: var(--accent-strong); }

.badge.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
.badge.primary:hover { background: var(--accent-strong); color: #fff; }

.badge.disabled {
  opacity: 0.55;
  cursor: default;
  pointer-events: none;
}

/* ---------- Hero teaser ---------- */

.teaser {
  margin: 40px auto 0;
}

.teaser-row { margin-bottom: 22px; }
.teaser-row:last-child { margin-bottom: 0; }

.teaser-label {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin: 0 0 8px 2px;
  text-align: left;
}
.teaser-note {
  font-weight: 400;
  text-transform: none;
  letter-spacing: normal;
  color: var(--text-muted);
  opacity: 0.8;
}

.teaser-grid {
  display: grid;
  gap: 6px;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--shadow);
}
.teaser-grid.cols-2 { grid-template-columns: 1fr 1fr; }
.teaser-grid.cols-3 { grid-template-columns: 1fr 1fr 1fr; }

.teaser-grid img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  display: block;
  -webkit-user-drag: none;
}

.teaser-cell {
  position: relative;
  overflow: hidden;
  background: #000;
}
.teaser-grid.cols-2 .teaser-cell { aspect-ratio: 1242 / 375; }
.teaser-grid.cols-3 .teaser-cell { aspect-ratio: 700 / 385; }
.teaser-cell .tag {
  position: absolute;
  bottom: 6px;
  left: 6px;
  background: rgba(0,0,0,0.6);
  color: #fff;
  font-size: 11px;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 5px;
}

@media (max-width: 560px) {
  .teaser-grid.cols-3 { grid-template-columns: 1fr 1fr; }
  .teaser-grid.cols-3 .teaser-cell:first-child { grid-column: 1 / -1; }
}

.teaser-video {
  display: block;
  width: 100%;
  border-radius: 10px;
  overflow: hidden;
  box-shadow: var(--shadow);
  background: #000;
  -webkit-user-drag: none;
}

/* ---------- Sections ---------- */

main { padding-bottom: 30px; }

section { padding: 56px 0; border-bottom: 1px solid var(--border); scroll-margin-top: 52px; }
section:last-of-type { border-bottom: none; }
main > section:nth-of-type(even) { background: var(--bg-alt); }

h2.section-title {
  font-family: var(--font-display);
  font-size: 1.55rem;
  font-weight: 700;
  margin: 0 0 22px;
  letter-spacing: -0.01em;
}

h3.sub-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 600;
  margin: 32px 0 12px;
  color: var(--text);
}

p.section-intro {
  color: var(--text-muted);
  max-width: 100%;
  margin-bottom: 24px;
}

.abstract-block {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px 32px;
  font-family: var(--font-serif);
  font-size: 1.08rem;
  line-height: 1.65;
  color: var(--text);
}
.abstract-block b { color: var(--accent-strong); font-weight: 600; }

/* ---------- Method ---------- */

.method-figure {
  text-align: center;
  margin: 8px 0 20px;
}
.method-figure img {
  max-width: 100%;
  border-radius: 10px;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}
.method-figure figcaption {
  max-width: none;
  margin: 10px 0 0;
  text-align: left;
}
figcaption, .fig-caption {
  font-size: 0.85rem;
  color: var(--text-muted);
  max-width: 760px;
  margin: 10px auto 0;
  text-align: left;
}

.method-cols {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.callout-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 20px;
}
@media (max-width: 680px) { .callout-grid { grid-template-columns: 1fr; } }

.callout {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: 8px;
  padding: 16px 18px;
}
.callout h4 {
  margin: 0 0 6px;
  font-size: 0.98rem;
  color: var(--accent-strong);
}
.callout p { margin: 0; font-size: 0.92rem; color: var(--text-muted); }

/* ---------- VLM chain-of-thought block ---------- */

.vlm-block {
  display: grid;
  grid-template-columns: minmax(120px, 160px) 1fr;
  grid-auto-rows: min-content;
  column-gap: 20px;
  row-gap: 14px;
  align-items: stretch;
}

.vlm-img-cell {
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.vlm-img-cell img {
  width: 100%;
  border-radius: 8px;
  display: block;
  box-shadow: var(--shadow);
}
.vlm-img-cell.ours img { outline: 2px solid var(--accent); outline-offset: -2px; }
.vlm-img-cell .lbl {
  font-size: 0.75rem;
  color: var(--text-muted);
  text-align: center;
  margin-top: 4px;
}
.vlm-img-cell.ours .lbl { color: var(--accent-strong); font-weight: 700; }
.vlm-img-cell .lbl .psi-icon { height: 0.68em; }

.vlm-cot-block {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-left: 3px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.vlm-cot-block.ours { border-left-color: var(--accent); background: var(--accent-soft); }
.vlm-cot-block p { margin: 0 0 6px; font-family: var(--font-serif); font-size: 0.82rem; color: var(--text); line-height: 1.5; }
.vlm-cot-block p:last-child { margin-bottom: 0; }
.vlm-cot-block em { font-family: var(--font-mono); color: var(--text-muted); font-style: normal; font-weight: 700; font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.03em; }
.vlm-cot-label {
  font-size: 0.78rem !important;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  color: var(--text-muted) !important;
  margin-bottom: 8px !important;
}
.vlm-cot-block.ours .vlm-cot-label { color: var(--accent-strong) !important; }
.vlm-cot-label .psi-icon { height: 0.68em; }

@media (max-width: 680px) {
  .vlm-block { grid-template-columns: 1fr; }
}

/* ---------- 2D image comparison (drag X = input/ours, drag Y = ours/baseline) ---------- */

.compare-label {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--text-muted);
  margin: 0 0 8px;
}

.compare-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 10px;
}
.compare-row .compare-label { margin: 0; }
.comp2d-wrap > .compare-row { margin-top: 0; margin-bottom: 10px; }

.baseline-select {
  padding: 6px 30px 6px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg-alt);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20' fill='%2355595f'%3E%3Cpath d='M5.5 7.5l4.5 4.5 4.5-4.5' stroke='%2355595f' stroke-width='1.6' fill='none' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 8px center;
  background-size: 16px;
}
.baseline-select:focus { outline: 2px solid var(--accent); outline-offset: 1px; }

/* Subway-style step indicator showing which example is active */
.scene-progress {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  max-width: 280px;
  margin: 0 auto 16px;
}
.progress-dot {
  flex: 0 0 auto;
  width: 11px; height: 11px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--border);
  padding: 0;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}
.progress-dot:hover { border-color: var(--accent); }
.progress-dot.active { background: var(--accent); border-color: var(--accent); transform: scale(1.4); }

/* Carousel arrows flanking the comparison image */
.comp2d-carousel {
  position: relative;
}
#vkitti-2d, #carla-2d, #instance-2d { min-width: 0; }

#results-image .comp2d-carousel,
#results-video .comp2d-carousel,
#instance .comp2d-carousel,
#results-image .fig-caption,
#results-video .fig-caption,
#instance .fig-caption,
#results-image .section-intro,
#results-video .section-intro,
#instance .section-intro,
#results-image .scene-progress,
#results-video .scene-progress,
#instance .scene-progress {
  max-width: 1120px;
  margin-left: auto;
  margin-right: auto;
}

.carousel-arrow {
  position: absolute;
  top: 50%;
  z-index: 3;
  width: 42px; height: 42px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-alt);
  color: var(--text);
  font-size: 1.3rem;
  line-height: 1;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow);
  transform: translateY(-50%);
  transition: background 0.12s ease, border-color 0.12s ease, color 0.12s ease;
}
.carousel-arrow.left { left: 12px; }
.carousel-arrow.right { right: 12px; }
.carousel-arrow:hover { background: var(--accent); border-color: var(--accent); color: #fff; }

@media (max-width: 640px) {
  .carousel-arrow { width: 32px; height: 32px; font-size: 1.05rem; }
  .carousel-arrow.left { left: 8px; }
  .carousel-arrow.right { right: 8px; }
}

.comp2d {
  position: relative;
  width: 100%;
  border-radius: 10px;
  overflow: hidden;
  background: #000;
  box-shadow: var(--shadow);
  cursor: crosshair;
  user-select: none;
  touch-action: none;
  margin-bottom: 6px;
}
.comp2d .layer {
  position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; display: block;
  -webkit-user-drag: none;
  user-select: none;
  pointer-events: none;
}
.comp2d .layer.ours { clip-path: inset(0 0 50% 0); }
.comp2d .layer.input { clip-path: inset(0 50% 0 0); }

.instance-highlight {
  position: absolute;
  top: 42px;
  left: 10px;
  width: min(180px, calc(50% - 20px));
  max-height: 40%;
  object-fit: contain;
  border-radius: 8px;
  border: 1px solid rgba(255,255,255,0.7);
  box-shadow: 0 10px 24px rgba(0,0,0,0.28);
  background: rgba(0,0,0,0.35);
  z-index: 2;
  pointer-events: none;
}

@media (max-width: 640px) {
  .instance-highlight {
    top: 38px;
    width: min(120px, calc(50% - 18px));
    max-height: 34%;
  }
}

.comp2d .v-div {
  position: absolute; top: 0; bottom: 0; left: 50%;
  width: 2px; background: rgba(255,255,255,0.8);
  transform: translateX(-50%); pointer-events: none;
}
.comp2d .h-div {
  position: absolute; left: 0; right: 0; top: 50%;
  height: 2px; background: rgba(255,255,255,0.8);
  transform: translateY(-50%); pointer-events: none;
  clip-path: inset(0 0 0 50%);
}
.comp2d .crosshair {
  position: absolute; left: 50%; top: 50%;
  width: 34px; height: 34px; border-radius: 50%;
  background: rgba(0,0,0,0.45); backdrop-filter: blur(6px);
  border: 2px solid rgba(255,255,255,0.7);
  transform: translate(-50%, -50%);
  pointer-events: none;
}
.tag2d {
  position: absolute;
  font-family: var(--font-mono);
  font-size: 11px; font-weight: 600;
  padding: 3px 10px; border-radius: 6px;
  color: #fff; pointer-events: none;
}
.tag2d.tl { top: 10px; left: 10px; background: rgba(0,0,0,0.6); }
.tag2d.tr { top: 10px; right: 10px; background: var(--accent); }
.tag2d.br { bottom: 10px; right: 10px; background: var(--warm); }

.demo-clip {
  display: block;
  width: 100%;
  max-width: 640px;
  margin: 0 auto 24px;
  border-radius: 10px;
  box-shadow: var(--shadow);
  background: #000;
}


/* ---------- BibTeX ---------- */

.bibtex-block {
  position: relative;
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 20px 22px;
}
.bibtex-block pre {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  white-space: pre-wrap;
  word-break: break-word;
  color: var(--text);
}
.copy-btn {
  position: absolute;
  top: 14px; right: 14px;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 5px 12px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg);
  color: var(--text-muted);
  cursor: pointer;
}
.copy-btn:hover { border-color: var(--accent); color: var(--accent-strong); }

/* ---------- Footer ---------- */

footer {
  padding: 34px 0 60px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}
footer a { color: var(--text-muted); }

a { color: var(--accent-strong); }

.notice {
  font-size: 0.82rem;
  color: var(--text-muted);
  background: var(--bg-alt);
  border: 1px dashed var(--border);
  border-radius: 8px;
  padding: 10px 14px;
  margin-top: 14px;
}