:root {
  --bg: #fbfaf8;
  --surface: #ffffff;
  --surface-2: #f2f0ec;
  --ink: #1b1d24;
  --ink-2: #4a4e5a;
  --ink-3: #737885;
  --line: #e2dfd8;
  --accent: #2f5bd3;
  --accent-ink: #ffffff;
  --stage: #0d0f16;
  --radius: 12px;
  --sans: Inter, system-ui, -apple-system, "Segoe UI", sans-serif;
  --serif: "Source Serif 4", Georgia, serif;
  color-scheme: light;
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 var(--sans);
}

.topbar, main, .masthead, .footer {
  width: min(1120px, 100% - 32px);
  margin-inline: auto;
}

/* Top bar -------------------------------------------------------------- */

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--ink-2);
  font-size: 14px;
  font-weight: 500;
  line-height: 1.3;
}

.logo {
  display: block;
  width: auto;
}

.logo-bgu { height: 44px; }
.logo-neurips { height: 56px; }

/* Masthead ------------------------------------------------------------- */

.masthead {
  padding: 44px 0 28px;
  text-align: center;
}

h1 {
  margin: 0 auto 20px;
  max-width: 900px;
  font: 600 clamp(26px, 4.2vw, 42px)/1.18 var(--serif);
  letter-spacing: -0.01em;
  text-wrap: balance;
}

.authors {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 22px;
  margin: 0 0 8px;
  font-size: 18px;
  font-weight: 500;
}

.authors a {
  color: inherit;
  text-decoration: underline;
  text-decoration-color: var(--line);
  text-decoration-thickness: 1px;
  text-underline-offset: 4px;
}

.authors a:hover {
  color: var(--accent);
  text-decoration-color: currentColor;
}

.affiliations {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0 0 22px;
  color: var(--ink-3);
  font-size: 14px;
}

.links {
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}

.pill {
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--ink);
  color: var(--bg);
  font-weight: 500;
  font-size: 15px;
  text-decoration: none;
}

.pill:hover { opacity: 0.85; }

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

section { margin: 0 0 56px; }

.prose {
  max-width: 760px;
  margin-inline: auto;
}

h2 {
  margin: 0 0 14px;
  font: 600 26px/1.25 var(--serif);
}

h3 {
  margin: 0 0 10px;
  font: 600 20px/1.3 var(--serif);
}

.prose p {
  color: var(--ink-2);
  text-align: justify;
  hyphens: auto;
}

.hero-title {
  margin: 16px 0 18px;
  text-align: center;
  text-wrap: balance;
}

.caption {
  max-width: 760px;
  margin: 16px auto 0;
  color: var(--ink-2);
  font-size: 15px;
  text-align: center;
}

.prose a {
  color: var(--accent);
  text-underline-offset: 3px;
}

.display-math {
  overflow-x: auto;
  padding: 8px 0;
}

/* Intro: what diffeomorphisms and CPAB are ---------------------------------- */

.intro h3 { margin-top: 36px; }

.intro img {
  display: block;
  width: 100%;
  height: auto;
}

.intro-cartoon {
  max-width: 760px;
  margin: 0 auto 28px;
}

.figure-pair {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 24px;
  max-width: 760px;
  margin: 8px auto 20px;
}

/* Column widths follow the aspect ratios (1 : 1.2) so both images share one height. */
.figure-pair-cpab { grid-template-columns: minmax(0, 1fr) minmax(0, 1.2fr); }

.figure-pair figure { margin: 0; }

.figure-pair figcaption, .benchmark figcaption {
  margin-top: 8px;
  color: var(--ink-3);
  font-size: 14px;
  line-height: 1.45;
  text-align: center;
}

/* Gradient benchmark ------------------------------------------------------ */

.benchmark { margin: 20px 0 24px; }

.benchmark img {
  display: block;
  width: 100%;
  height: auto;
}

.benchmark figcaption { text-align: left; }

.prose p.takeaway {
  padding: 12px 16px;
  border-left: 3px solid var(--accent);
  border-radius: 0 8px 8px 0;
  background: var(--surface);
  color: var(--ink);
  text-align: left;
}

.highlights {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  max-width: 900px;
  margin-inline: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--line);
  overflow: hidden;
}

.highlights div {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 18px 20px;
  background: var(--surface);
}

.highlights strong {
  font: 600 26px/1.1 var(--serif);
  font-variant-numeric: tabular-nums;
}

.highlights span {
  color: var(--ink-3);
  font-size: 14px;
  line-height: 1.4;
}

.bibtex {
  margin: 0;
  padding: 16px 18px;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-2);
  font-size: 13px;
  line-height: 1.5;
}

.footer {
  padding: 24px 0 48px;
  border-top: 1px solid var(--line);
  color: var(--ink-3);
  font-size: 13px;
  text-align: center;
}

/* Demos ---------------------------------------------------------------- */

.demo {
  display: grid;
  gap: 20px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 4px);
  background: var(--surface);
}

.demo-sculpt {
  grid-template-columns: minmax(0, 560px) minmax(0, 1fr);
  align-items: start;
}

.demo-stage {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  background: var(--stage);
}

.demo-stage.square { aspect-ratio: 1; }

/* The sculpt image is often light up to its edges: outline it so it stands off the card. */
.demo-sculpt .demo-stage {
  box-shadow: 0 1px 2px rgba(27, 29, 36, 0.08), 0 6px 18px rgba(27, 29, 36, 0.10);
}

.demo-sculpt .demo-stage::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  box-shadow: inset 0 0 0 1px rgba(27, 29, 36, 0.22);
  pointer-events: none;
}

.demo-canvas {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
  cursor: grab;
}

.demo-canvas:active { cursor: grabbing; }

.demo-hint {
  position: absolute;
  left: 50%;
  bottom: 14px;
  transform: translateX(-50%);
  padding: 6px 14px;
  border-radius: 999px;
  background: rgba(10, 12, 20, 0.72);
  color: #fff;
  font-size: 14px;
  pointer-events: none;
  white-space: nowrap;
  transition: opacity 0.4s;
}

.demo-hint.hidden { opacity: 0; }

/* The note shown after the first warp of the test card. */
.demo-toast {
  position: absolute;
  bottom: 14px;
  left: 50%;
  width: min(380px, calc(100% - 28px));
  padding: 14px 16px;
  border-radius: var(--radius);
  background: rgba(10, 12, 20, 0.86);
  color: #fff;
  font-size: 14px;
  line-height: 1.45;
  transform: translateX(-50%);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.25);
  animation: toast-in 0.35s ease-out;
}

.demo-toast p { margin: 0 24px 10px 0; }

.demo-toast-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.demo-toast .demo-toast-close {
  position: absolute;
  top: 6px;
  right: 6px;
  min-height: 0;
  padding: 2px 8px;
  border: 0;
  background: none;
  color: rgba(255, 255, 255, 0.75);
  font-size: 18px;
  line-height: 1;
}

@keyframes toast-in {
  from { opacity: 0; transform: translate(-50%, 8px) rotate(-1.5deg); }
  to { opacity: 1; transform: translateX(-50%); }
}

.demo-panel {
  display: flex;
  flex-direction: column;
  gap: 18px;
  min-width: 0;
}

.demo-controls {
  display: grid;
  gap: 12px;
}

.ctl {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr) 64px;
  align-items: center;
  gap: 12px;
  font-size: 14px;
}

.ctl-name { color: var(--ink-2); }

.ctl output {
  color: var(--ink);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.ctl select {
  grid-column: 2 / 4;
}

.ctl:has(:disabled) { opacity: 0.45; }
.ctl :disabled { cursor: not-allowed; }

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
}

.demo-buttons {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.demo-buttons .sep {
  flex-basis: 100%;
  height: 0;
}

button, select {
  min-height: 36px;
  padding: 6px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--surface-2);
  color: var(--ink);
  font: 500 14px var(--sans);
  cursor: pointer;
}

button:hover, select:hover { border-color: var(--ink-3); }

button[aria-pressed="true"] {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--accent-ink);
}

button:focus-visible, select:focus-visible, input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0 6px;
  color: var(--ink-2);
  font-size: 14px;
  cursor: pointer;
}

.toggle input { accent-color: var(--accent); }

.demo-stats {
  margin: 0;
  color: var(--ink-3);
  font-size: 13px;
  line-height: 1.5;
}

.demo-fallback {
  display: grid;
  place-items: center;
  min-height: 240px;
}

.demo-error {
  position: fixed;
  right: 16px;
  bottom: 16px;
  left: 16px;
  z-index: 10;
  max-width: 720px;
  margin-inline: auto;
  padding: 12px 16px;
  border: 1px solid #d9433b;
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--ink-2);
  font-size: 13px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.18);
  cursor: pointer;
}

.demo-error strong { color: var(--ink); }

.demo-error p {
  margin: 4px 0 0;
  overflow-wrap: anywhere;
}

.fallback-note {
  max-width: 420px;
  padding: 20px;
  color: #d6d8df;
  font-size: 14px;
  text-align: center;
}

/* Registration demo ------------------------------------------------------ */

.demo-register { grid-template-columns: 1fr; }

.panels {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.panel figure, figure.panel {
  margin: 0;
  min-width: 0;
}

.panel figcaption {
  margin-top: 6px;
  color: var(--ink-2);
  font-size: 13px;
  text-align: center;
}

.panel .demo-stage { aspect-ratio: 1; }

.panels.three { grid-template-columns: repeat(3, minmax(0, 1fr)); }

/* Line-color key in a caption: set --key on the element. */
.key {
  display: inline-block;
  width: 14px;
  height: 3px;
  margin: 0 5px 0 2px;
  border-radius: 2px;
  background: var(--key);
  vertical-align: middle;
}

.nowrap { white-space: nowrap; }

.register-bottom {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
  gap: 20px;
  align-items: start;
}

.loss-plot {
  display: block;
  width: 100%;
  height: 150px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-2);
}

.metrics {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 8px;
  margin-top: 10px;
}

.metrics div {
  display: flex;
  flex-direction: column;
  padding: 8px 10px;
  border-radius: 8px;
  background: var(--surface-2);
}

.metrics strong {
  font-size: 17px;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.metrics span {
  color: var(--ink-3);
  font-size: 12px;
}

.metrics .formula { white-space: nowrap; }

/* Face alignment demo ------------------------------------------------------ */

/* The panels only display, so a swipe over them scrolls the page. */
.demo-faces .demo-canvas {
  touch-action: auto;
  cursor: default;
}

.demo-faces .metrics {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin-top: 0;
}

.demo-faces .metrics + .demo-stats { margin-top: 14px; }

/* Overlays on the source panel: the webcam and upload buttons while it is
   empty, and short notes along its bottom edge. */
.stage-cta {
  position: absolute;
  top: 45%;
  left: 50%;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transform: translate(-50%, -50%);
}

.stage-cta button {
  padding: 6px 12px;
  border-color: var(--accent);
  background: var(--accent);
  color: var(--accent-ink);
  font-size: 13px;
  white-space: nowrap;
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.3);
}

.stage-cta button:hover { border-color: var(--accent); opacity: 0.9; }

.stage-note {
  position: absolute;
  left: 50%;
  bottom: 10px;
  transform: translateX(-50%);
  width: max-content;
  max-width: calc(100% - 20px);
  padding: 4px 12px;
  border-radius: 10px;
  background: rgba(10, 12, 20, 0.72);
  color: #fff;
  font-size: 13px;
  line-height: 1.4;
  text-align: center;
  pointer-events: none;
}

.demo-credits {
  margin: -8px 0 0;
  color: var(--ink-3);
  font-size: 12px;
}

.demo-credits a { color: inherit; }

/* Responsive ------------------------------------------------------------- */

@media (max-width: 860px) {
  .demo-sculpt { grid-template-columns: 1fr; }
  .panels { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .register-bottom { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  .brand { gap: 8px; font-size: 12px; }
  .logo-bgu { height: 34px; }
  .logo-neurips { height: 44px; }
  .masthead { padding-top: 32px; }
  .demo { padding: 12px; }
  .ctl { grid-template-columns: 96px minmax(0, 1fr) 52px; gap: 8px; }
  .highlights { grid-template-columns: 1fr; }
  .figure-pair, .figure-pair-cpab { grid-template-columns: 1fr; max-width: 400px; }
  .metrics { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .panels { gap: 6px; }
  /* Three panels are too small to read on a phone: drop the least needed one and show the other two larger. */
  .panels.three { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .panels .wide-only { display: none; }
  .panel figcaption { font-size: 11px; line-height: 1.35; }
}