/* ---------- Theme tokens ---------- */
:root {
  --bg: #ffffff;
  --bg-alt: #fafafa;
  --surface: #ffffff;
  --text: #111111;
  --text-soft: #4a4a4a;
  --text-mute: #8a8a8a;
  --border: #ececec;
  --border-strong: #d8d8d8;
  --accent: #111111;
  /* Single knob for the brand color used by the logo, title, bullets and "ours" highlight. */
  --brand: #f27100;
  /* Opaque on purpose: this sits on the black video cell, where a translucent
     tint would read as dark brown rather than as a light wash. */
  --brand-soft: #fdf1e5;
  --link: #2a5db0;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 14px;
  --maxw: 1225px;
  --maxw-narrow: 862px;
}

/* ---------- Base ---------- */
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 64px; }
body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, system-ui, 'Helvetica Neue', Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "ss01", "cv11";
}

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

.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 32px;
}
.container.narrow { max-width: var(--maxw-narrow); }

/* ---------- Nav ---------- */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(8px);
  -webkit-backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid transparent;
}
.nav.scrolled { border-bottom-color: var(--border); }

.nav-inner {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 16px 32px;
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-logo {
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--brand);
  font-size: 15px;
}
.nav-logo:hover { text-decoration: none; }

.nav-links {
  display: flex;
  gap: 24px;
  flex: 1;
  justify-content: flex-end;
  flex-wrap: wrap;
}
.nav-links a {
  color: var(--text-soft);
  font-weight: 400;
  font-size: 14px;
  white-space: nowrap;
}
.nav-links a:hover { color: var(--text); text-decoration: none; }

/* ---------- Hero ---------- */
.hero {
  padding: 40px 0 0;
  text-align: center;
}

.title {
  font-size: clamp(28px, 4vw, 42px);
  line-height: 1.2;
  font-weight: 600;
  letter-spacing: -0.015em;
  margin: 0 auto 28px;
  max-width: 1160px;
  color: var(--text);
}
.title-row { display: block; }
.title-accent { display: block; }
.title-brand { color: var(--brand); }

.authors {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: baseline;
  gap: 4px 18px;
  margin: 0 0 6px;
  font-size: 17.5px;
  color: var(--text);
}
.author { white-space: nowrap; }
.author sup {
  color: var(--text-mute);
  font-weight: 400;
  font-size: 0.7em;
  line-height: 0;
  position: relative;
  top: -0.45em;
  vertical-align: baseline;
}

.affiliations {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 16px;
  font-size: 15.5px;
  color: var(--text-mute);
  margin-bottom: 6px;
}

.equal-contrib {
  text-align: center;
  font-size: 13px;
  color: var(--text-mute);
  margin-bottom: 16px;
}
.equal-contrib sup { margin-right: 2px; }

.links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}
.link-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  background: var(--accent);
  color: #fff;
  border-radius: 999px;
  font-weight: 600;
  font-size: 13.5px;
  letter-spacing: 0.01em;
  border: 1px solid var(--accent);
  transition: background 0.15s ease, border-color 0.15s ease;
}
.link-btn:hover {
  text-decoration: none;
  background: #2a2a2a;
  border-color: #2a2a2a;
}
.link-btn svg { width: 14px; height: 14px; }

/* ---------- Teaser ---------- */
.teaser-wrap {
  position: relative;
  max-width: 900px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: #000;
}
.teaser-video {
  width: 100%;
  display: block;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: #000;
}
.teaser-caption {
  max-width: 900px;
  margin: 12px auto 0;
  text-align: center;
  font-size: 14px;
  color: var(--text-mute);
}

/* ---------- Sections ---------- */
.section { padding: 48px 0; }
.section-tight { padding: 24px 0 40px; }
.section-alt { background: var(--bg-alt); }

.section-head { text-align: center; margin-bottom: 26px; }
.section-title {
  font-size: clamp(22px, 2.6vw, 28px);
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 0 0 8px;
  color: var(--text);
  text-align: center;
}
.section-sub {
  margin: 0;
  color: var(--text-mute);
  font-size: 15px;
}
.scroll-hint {
  display: inline-block;
  margin-left: 6px;
  font-size: 13px;
  color: var(--text-mute);
  opacity: 0.75;
}
/* `display: inline-block` above would otherwise beat the UA [hidden] rule. */
.scroll-hint[hidden] { display: none; }

/* ---------- Method text ---------- */
.lead {
  font-size: 17px;
  line-height: 1.8;
  color: var(--text-soft);
  margin: 0;
}
.lead em { color: var(--text-mute); font-style: normal; }
.lead strong { color: var(--text); font-weight: 600; }

/* The method name, wherever it appears in prose. */
.lead .brand-name,
.method-points .brand-name { color: var(--brand); font-weight: 600; }

.method-points {
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 13px;
}
.method-points li {
  position: relative;
  padding-left: 21px;
  font-size: 17px;
  line-height: 1.7;
  color: var(--text-soft);
}
.method-points li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.62em;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--brand);
}
.method-points strong { color: var(--text); font-weight: 600; }

.method-figure {
  margin: 28px 0 0;
  background: var(--surface);
  border-radius: var(--radius-md);
  padding: 24px;
  border: 1px solid var(--border);
}
.method-figure img { width: 100%; height: auto; display: block; }

/* ---------- RTC mode toggle ---------- */
/* ---------- Real-time banner ---------- */
.realtime-banner {
  display: flex;
  align-items: center;
  gap: 10px;
  max-width: 720px;
  margin: 0 auto 18px;
  padding: 11px 18px;
  border: 1px solid var(--brand);
  border-radius: 999px;
  background: var(--brand-soft);
  color: var(--text-soft);
  font-size: 14px;
  line-height: 1.5;
  text-align: left;
}
.realtime-banner svg {
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  color: var(--brand);
}
.realtime-banner strong { color: var(--brand); font-weight: 600; }

@media (max-width: 620px) {
  .realtime-banner { border-radius: var(--radius-md); align-items: flex-start; }
}

/* ---------- Playback-speed chip ---------- */
.speed-chip {
  position: absolute;
  top: 8px;
  right: 8px;
  z-index: 3;
  padding: 2px 8px;
  border-radius: 999px;
  background: rgba(0, 0, 0, 0.55);
  border: 1px solid rgba(255, 255, 255, 0.3);
  color: #fff;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.02em;
  line-height: 1.5;
  pointer-events: none;
  backdrop-filter: blur(2px);
  -webkit-backdrop-filter: blur(2px);
}
/* 1x on the rollouts is the paper's claim, so it gets the brand color. */
.speed-chip.is-realtime {
  background: var(--brand);
  border-color: var(--brand);
}

/* ---------- Rollout rows (one row per task) ---------- */
.task-block { margin-bottom: 40px; }
.task-block:last-child { margin-bottom: 0; }

.task-block-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}
.task-block-name {
  margin: 0;
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.005em;
  color: var(--text);
}
.task-block-desc {
  margin: 0;
  font-size: 14px;
  color: var(--text-mute);
}

/* Scrollable flex row: the row also carries .scroll-row, which supplies the
   overflow, wheel/drag and scrollbar styling. The plain baselines fill the
   first screenful; the w/-RTC variants sit past the right edge. */
.video-row { gap: 12px; }
.video-row > .video-cell { flex: 0 0 min(235px, 70vw); }
/* Ours lives outside the scroller, so it stays put while only the baselines
   scroll beside it — nothing slides underneath, the row just clips at its own
   left edge. */
.video-row-wrap {
  display: flex;
  gap: 12px;
  align-items: flex-start;
}
.video-row-wrap > .video-cell.is-ours { flex: 0 0 min(235px, 70vw); }
.video-row-wrap > .video-row { flex: 1; min-width: 0; }

.video-cell {
  position: relative;
  margin: 0;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: #000;
}
.video-cell video {
  width: 100%;
  display: block;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: #000;
  /* Rollout clips are display-only: no hover, pause or seek. */
  pointer-events: none;
}
.video-cell .video-label {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 6px;
  padding: 7px 8px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-soft);
  text-align: center;
}
.video-cell .video-label .label-sub {
  font-size: 11.5px;
  font-weight: 500;
  color: var(--text-mute);
}

/* Our method: brand-colored label. */
.video-cell.is-ours .video-label {
  color: var(--brand);
  background: var(--brand-soft);
  border-top-color: var(--brand);
}
.video-cell.is-ours .video-label .label-sub { color: var(--brand); opacity: 0.8; }

/* ---------- Horizontal scroll row (rollouts + training) ---------- */
.scroll-row-wrap { position: relative; }
.scroll-row {
  display: flex;
  gap: 16px;
  overflow-x: auto;
  scroll-behavior: smooth;
  /* No scroll-snap: Chrome re-snaps to a card edge after every scroll (even
     with proximity), which yanks the row back to the start and makes it feel
     unscrollable. */
  padding-bottom: 8px;
  -webkit-overflow-scrolling: touch;
  cursor: grab;
}
/* While the mouse is dragging the row, scroll must track the pointer 1:1. */
.scroll-row.dragging {
  cursor: grabbing;
  scroll-behavior: auto;
  user-select: none;
}
.scroll-row::-webkit-scrollbar { height: 6px; }
.scroll-row::-webkit-scrollbar-thumb { background: var(--border-strong); border-radius: 999px; }
/* Fixed card width so the row keeps its horizontal scroll instead of the cards
   stretching to fill it. */
.scroll-row > * {
  flex: 0 0 min(340px, 84vw);
}

.scroll-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 5;
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border-radius: 999px;
  border: 1px solid var(--border-strong);
  background: rgba(255, 255, 255, 0.92);
  color: var(--text);
  cursor: pointer;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  transition: background 0.15s ease, opacity 0.15s ease;
}
.scroll-btn svg { width: 18px; height: 18px; }
.scroll-btn[hidden] { display: none; }
.scroll-btn:hover { background: #fff; }
.scroll-btn[disabled] { opacity: 0.25; cursor: default; }
.scroll-btn-left { left: -14px; }
.scroll-btn-right { right: -14px; }
@media (max-width: 1300px) {
  .scroll-btn-left { left: 4px; }
  .scroll-btn-right { right: 4px; }
}

.card {
  position: relative;
  margin: 0;
  background: #000;
  border-radius: var(--radius-md);
  overflow: hidden;
  border: 1px solid var(--border);
}
.card video {
  width: 100%;
  display: block;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: #000;
  /* The training recordings come from a different camera pipeline than the
   * phone footage in the rollout/evaluation sections and read a bit darker and
   * flatter. A light touch in the browser instead of re-encoding; kept subtle
   * on purpose -- a stronger grade looked artificial. */
  filter: brightness(1.12) contrast(1.04) saturate(1.1);
}
/* Ball balancing is lit a touch brighter than the rest: same grade, 10% dimmer. */
.card[data-task="balance"] video {
  filter: brightness(1.008) contrast(1.04) saturate(1.1);
}
/* Dynamic pick keeps its native colors (no grade), only the crop below. */
.card[data-task="dynamic_pick"] video {
  filter: none;
  /* Trim the left 3% of the frame: scale by 1/0.97 anchored on the right edge,
   * so the cut-off strip falls outside the card (overflow hidden) and the rest
   * fills the same box. */
  transform: scale(1.031);
  transform-origin: 100% 50%;
}
.card figcaption {
  padding: 8px 10px;
  background: var(--surface);
  border-top: 1px solid var(--border);
  font-size: 13px;
  font-weight: 600;
  color: var(--text-soft);
  text-align: center;
}

/* ---------- Evaluation ---------- */
.task-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  justify-content: flex-start;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--border);
}
.task-tab {
  padding: 10px 16px;
  border: none;
  background: transparent;
  color: var(--text-mute);
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  font-size: 14px;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
}
.task-tab:hover { color: var(--text); }
.task-tab.active {
  color: var(--text);
  border-bottom-color: var(--text);
}

.eval-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  gap: 24px;
  /* Both columns share one height: the 16:9 video sets it and the results
     card stretches to match (its note is pinned to the bottom edge). */
  align-items: stretch;
}
@media (max-width: 900px) {
  .eval-layout { grid-template-columns: 1fr; }
}

.task-stage {
  position: relative;
  background: #000;
  border-radius: var(--radius-lg);
  overflow: hidden;
}
.task-video {
  width: 100%;
  height: 100%;
  display: block;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  background: #000;
}
.task-info {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  padding: 18px 20px;
  text-shadow: 0 1px 3px rgba(0, 0, 0, 0.55);
  pointer-events: none;
}
.task-info h3 {
  margin: 0 0 4px;
  font-size: 16px;
  font-weight: 600;
  color: #fff;
}
.task-info p {
  margin: 0;
  color: rgba(255, 255, 255, 0.85);
  font-size: 14px;
}

.eval-results {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 18px 22px;
  display: flex;
  flex-direction: column;
  min-height: 0;
}
.eval-results-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--text-mute);
  margin-bottom: 12px;
}
.eval-legend {
  display: flex;
  gap: 12px;
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.02em;
  text-transform: none;
}
.eval-legend > span { display: inline-flex; align-items: center; gap: 5px; }
.eval-swatch {
  display: inline-block;
  width: 14px;
  height: 6px;
  border-radius: 999px;
  background: var(--text-mute);
}
.eval-swatch.is-nortc { background: #d4d4d4; }
#eval-bars { flex: 1; }
.eval-bar-row { margin-bottom: 11px; }
.eval-bar-head {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 5px;
  font-size: 13.5px;
}
.eval-bar-name { color: var(--text-soft); font-weight: 500; }
.eval-bar-row.is-ours .eval-bar-name { color: var(--brand); font-weight: 600; }
.eval-bar-vals { display: inline-flex; gap: 10px; }
.eval-bar-val {
  font-family: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 12.5px;
  color: var(--text-mute);
}
.eval-bar-val.is-nortc { color: #b4b4b4; }
.eval-bar-row.is-ours .eval-bar-val { color: var(--brand); }
.eval-bar-track {
  height: 8px;
  border-radius: 999px;
  background: #eeeeee;
  overflow: hidden;
}
.eval-bar-fill {
  height: 100%;
  border-radius: 999px;
  background: var(--text-mute);
  width: 0;
  transition: width 0.45s cubic-bezier(0.4, 0, 0.2, 1);
}
.eval-bar-row.is-ours .eval-bar-fill { background: var(--brand); }
/* Second, lighter bar: the same baseline run w/o RTC. */
.eval-bar-track.is-nortc { margin-top: 3px; height: 6px; }
.eval-bar-track.is-nortc .eval-bar-fill { background: #d4d4d4; }

.eval-note {
  margin: 14px 0 0;
  font-size: 12.5px;
  color: var(--text-mute);
}

/* ---------- Missing-video placeholder ---------- */
.video-missing {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 12px;
  text-align: center;
  background: #f4f4f4;
  border: 1px dashed var(--border-strong);
  border-radius: inherit;
  font-family: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 11px;
  line-height: 1.5;
  color: var(--text-mute);
  z-index: 2;
}

/* ---------- BibTeX ---------- */
.code-wrap { position: relative; }
.code {
  margin: 0;
  padding: 20px 22px;
  background: #fafafa;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  overflow-x: auto;
  font-family: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 13px;
  line-height: 1.7;
  color: var(--text-soft);
}
.copy-btn {
  position: absolute;
  top: 12px;
  right: 12px;
  padding: 5px 12px;
  background: #fff;
  border: 1px solid var(--border-strong);
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  font-family: inherit;
  color: var(--text-soft);
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}
.copy-btn:hover { background: var(--accent); color: #fff; border-color: var(--accent); }

/* ---------- Footer ---------- */
.footer {
  padding: 32px 0 48px;
  border-top: 1px solid var(--border);
  text-align: center;
}
.footer p {
  margin: 0;
  font-size: 13px;
  color: var(--text-mute);
}

@media (max-width: 640px) {
  .container { padding: 0 20px; }
  .nav-inner { padding: 12px 20px; gap: 16px; }
  .nav-links { gap: 14px; }
}