:root {
  --bg: #ffffff;
  --bg-soft: #f5f7fa;
  --text: #16181d;
  --muted: #5b6270;
  --line: #e3e7ee;
  --accent: #0a8fb8;
  --accent-soft: #e4f4fa;
  --radius: 12px;
  --max: 1120px;
  --narrow: 820px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.65 "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
img, video { display: block; max-width: 100%; }

.container { max-width: var(--max); margin: 0 auto; padding-left: 20px; padding-right: 20px; }
.narrow { max-width: var(--narrow); margin-left: auto; margin-right: auto; }
.container.narrow { max-width: calc(var(--narrow) + 40px); }
main > section { padding-top: 56px; padding-bottom: 56px; }
main > section + section { border-top: 1px solid var(--line); }
h2 { font-size: 1.75rem; font-weight: 700; letter-spacing: -0.02em; margin: 0 0 16px; }
h3 { font-size: 1.05rem; font-weight: 600; margin: 0 0 6px; }
.subhead { font-size: 1.25rem; font-weight: 700; letter-spacing: -0.01em; margin: 48px 0 14px; }
section p { margin: 0 0 12px; }
.muted, .note { color: var(--muted); }
.note { font-size: 0.93rem; margin-top: 12px; }

/* Hero: teaser video full width with the title over its lower edge. */
.hero-media {
  position: relative; display: flex; align-items: flex-end; width: 100%;
  height: min(56.25vw, 92vh); min-height: 360px; overflow: hidden; background: #0d0f12;
}
.hero-video { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; object-position: 50% 0; }
.hero-shade { position: absolute; inset: 0; background: linear-gradient(to top, rgba(8, 10, 14, 0.82) 0%, rgba(8, 10, 14, 0.45) 22%, rgba(8, 10, 14, 0) 42%); }
.hero-title { position: relative; width: 100%; padding-bottom: 40px; text-align: center; color: #fff; }
h1 { margin: 0; }
h1 .acronym { display: block; font-size: clamp(2.4rem, 6.5vw, 4.6rem); font-weight: 800; letter-spacing: -0.02em; line-height: 1.05; text-shadow: 0 2px 24px rgba(0, 0, 0, 0.35); }
h1 .subtitle { display: block; max-width: 760px; margin: 12px auto 0; font-size: clamp(1.05rem, 2.4vw, 1.45rem); font-weight: 500; letter-spacing: -0.01em; line-height: 1.35; text-shadow: 0 1px 12px rgba(0, 0, 0, 0.45); }


/* Contribution cards */
.cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.card { padding: 22px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--bg-soft); }
.card p { margin: 0; color: var(--muted); font-size: 0.95rem; }
.card-num { display: block; margin-bottom: 8px; color: var(--accent); font-weight: 700; font-size: 0.85rem; }

/* Figures */
.figure { margin: 28px auto 0; }
.figure img { width: 100%; border-radius: var(--radius); border: 1px solid var(--line); background: #fff; }
.figure figcaption { margin-top: 12px; color: var(--muted); font-size: 0.93rem; }

/* Section heads and headline numbers */
.section-head { max-width: var(--narrow); margin-bottom: 24px; }
.section-head p { color: var(--muted); }
.section-head .task { padding: 10px 14px; border-radius: 8px; background: var(--accent-soft); color: var(--text); }
.task b { margin-right: 6px; color: var(--accent); text-transform: uppercase; font-size: 0.8rem; letter-spacing: 0.06em; }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-bottom: 28px; }
.stat { display: flex; flex-direction: column; gap: 2px; padding: 16px 18px; border-left: 3px solid var(--accent); background: var(--bg-soft); border-radius: 0 var(--radius) var(--radius) 0; }
.stat-val { font-size: 1.6rem; font-weight: 700; letter-spacing: -0.02em; line-height: 1.2; }
.stat-lbl { font-size: 0.88rem; line-height: 1.35; }
.stat-lbl small { color: var(--muted); font-size: 0.8rem; }

/* Video tiles: click to enlarge. Tiles keep each clip's own aspect ratio. */
.grid { --cols: 2; --gap: 20px; display: flex; flex-wrap: wrap; justify-content: center; align-items: flex-start; gap: var(--gap); margin-top: 24px; }
.grid > .tile { width: calc((100% - (var(--cols) - 1) * var(--gap)) / var(--cols)); }
.grid > .tile.wide { width: 100%; }
.grid > .tile.tile-square { width: min(100%, 560px); }
.grid-narrow { max-width: 760px; margin-left: auto; margin-right: auto; }
.grid-teleop { max-width: 900px; margin-left: auto; margin-right: auto; }
.tile { display: flex; flex-direction: column; gap: 8px; padding: 0; border: 0; background: none; color: inherit; font: inherit; text-align: left; cursor: zoom-in; }
.tile-media { position: relative; overflow: hidden; border-radius: 10px; background: #0d0f12; }
.tile-media.light { background: #fff; border: 1px solid var(--line); }
.tile-media video { width: 100%; height: auto; }
.tile:hover .tile-media { box-shadow: 0 0 0 2px var(--accent); }
.tile:focus-visible .tile-media { outline: 3px solid var(--accent); outline-offset: 2px; }
.tile.ours .tile-media { box-shadow: 0 0 0 2px var(--accent); }
.tile-title { font-size: 0.92rem; font-weight: 500; color: var(--muted); }
.tile.ours .tile-title { color: var(--accent); font-weight: 600; }
.badge { position: absolute; top: 8px; left: 8px; z-index: 1; padding: 2px 9px; border-radius: 999px; background: rgba(13, 15, 18, 0.72); color: #fff; font-size: 0.74rem; font-weight: 600; backdrop-filter: blur(4px); }
.video-badge { position: absolute; top: 12px; left: 12px; z-index: 1; display: inline-flex; align-items: center; gap: 8px; padding: 7px 12px; border-radius: 999px; background: #ffffffeb; border: 1px solid var(--line); box-shadow: 0 1px 4px rgba(0, 0, 0, .08); font-size: 0.85rem; font-weight: 600; color: var(--text); }
.video-badge .swatch { width: 12px; height: 12px; border-radius: 50%; background: #e06a6a; opacity: .75; }

/* 3x2 comparison grid of portrait real-robot clips */
.vgrid { display: grid; grid-template-columns: auto repeat(var(--cols), 1fr); gap: 12px 14px; align-items: center; margin-top: 18px; }
.vgrid video { width: 100%; border-radius: 10px; background: #0d0f12; }
.vgrid video.ours { box-shadow: 0 0 0 2px var(--accent); }
.col-label { margin: 0; text-align: center; font-weight: 600; font-size: 0.92rem; color: var(--muted); }
.vgrid .col-label:first-child { grid-column: 2; }
.ours-label { color: var(--accent) !important; }
.row-label { margin: 0; writing-mode: vertical-rl; transform: rotate(180deg); font-weight: 600; font-size: 0.92rem; color: var(--muted); }


/* Results tables */
.table-wrap { overflow-x: auto; margin-top: 28px; }
table { width: 100%; border-collapse: collapse; font-size: 0.95rem; font-variant-numeric: tabular-nums; }
th, td { padding: 11px 14px; text-align: center; border-bottom: 1px solid var(--line); }
th { font-size: 0.82rem; font-weight: 600; color: var(--muted); border-bottom: 1.5px solid var(--text); }
td.l, th.l { text-align: left; }
tr.ours td { background: var(--accent-soft); color: var(--accent); }
td[rowspan] { background: #fff !important; color: var(--text) !important; vertical-align: middle; }
tr.group td { border-top: 1px solid #c9cfd8; }

/* Interactive viewer frame; the border sits outside the content height reported by the viewer. */
.lab-frame { box-sizing: content-box; display: block; width: calc(100% - 2px); height: 820px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }

/* Lightbox */
.lightbox { width: min(1200px, 94vw); padding: 0; border: 0; border-radius: var(--radius); background: #000; color: #fff; overflow: visible; }
.lightbox::backdrop { background: rgba(0, 0, 0, 0.8); }
.lightbox video { width: 100%; max-height: 82vh; border-radius: var(--radius) var(--radius) 0 0; }
.lightbox-caption { margin: 0; padding: 10px 16px; font-size: 0.95rem; }
.lightbox-close { position: absolute; top: -44px; right: 0; width: 36px; height: 36px; border: 0; border-radius: 50%; background: #fff; color: #000; font-size: 1.4rem; line-height: 1; cursor: pointer; }


@media (max-width: 900px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
  .cards { grid-template-columns: 1fr; }
}
@media (max-width: 560px) {
  main > section { padding-top: 40px; padding-bottom: 40px; }
  .container { padding-left: 16px; padding-right: 16px; }
  .hero-media { display: block; height: auto; min-height: 0; background: none; overflow: visible; }
  .hero-video { position: static; aspect-ratio: 16 / 9; background: #0d0f12; }
  .hero-shade { display: none; }
  .hero-title { padding: 20px 16px 0; color: var(--text); }
  h1 .acronym, h1 .subtitle { text-shadow: none; }
  .grid { --cols: 1; }
}

/* Consistent centred section intros. */
.section-head { max-width: 760px; margin: 0 auto 24px; text-align: center; }
.subhead, .subhead + .muted, .note, .figure figcaption, .tile-title { text-align: center; }
.subhead + .muted { max-width: 760px; margin-left: auto; margin-right: auto; }

/* Simulation small multiples */
.simchart { position: relative; padding: 18px 18px 8px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
.simchart-legend { display: flex; flex-direction: column; align-items: center; gap: 6px; margin-bottom: 10px; font-size: 0.85rem; color: var(--muted); }
.simchart-legend > div { display: flex; flex-wrap: wrap; justify-content: center; gap: 6px 20px; }
.simchart-legend .key { display: inline-flex; align-items: center; gap: 7px; }
.simchart-legend i, .simchart-tooltip i { display: inline-block; width: 10px; height: 10px; border-radius: 50%; }
.simchart-pair { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.simchart-panel { margin: 0; }
.simchart-panel figcaption { margin: 0 0 -4px; text-align: center; font-size: 0.8rem; font-weight: 600; color: var(--text); }
.simchart-panel svg { width: 100%; height: auto; display: block; overflow: visible; }
.simchart .grid { stroke: #eceff3; stroke-width: 1; }
.simchart .tick { font-size: 10px; fill: var(--muted); font-variant-numeric: tabular-nums; }
.simchart .axis { font-size: 10.5px; fill: var(--muted); }
.simchart .crosshair { stroke: #9aa3b2; stroke-width: 1; }
.simchart-tooltip { position: absolute; z-index: 3; min-width: 220px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: #fff; box-shadow: 0 8px 24px rgba(16, 24, 40, 0.12); font-size: 0.8rem; pointer-events: none; }
.simchart-tooltip .tt-head { font-weight: 700; margin-bottom: 6px; }
.simchart-tooltip .tt-series { display: flex; align-items: center; gap: 6px; margin-top: 6px; font-weight: 600; }
.simchart-tooltip .tt-row { display: grid; grid-template-columns: 1fr auto auto; gap: 8px; color: var(--muted); }
.simchart-tooltip .tt-row b { color: var(--text); font-variant-numeric: tabular-nums; }
.simchart-tooltip .tt-row small { font-variant-numeric: tabular-nums; }
.simchart-groups { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
.simchart-group-title { margin: 0 0 4px !important; text-align: center; font-weight: 700; font-size: 0.95rem; }
@media (max-width: 760px) { .simchart-groups { grid-template-columns: 1fr; } }
.simchart-row-title { margin: 18px 0 6px !important; padding-top: 14px; border-top: 1px solid var(--line); font-weight: 700; font-size: 1rem; color: var(--text); text-align: center; }
.simchart-legend + .simchart-row-title { margin-top: 4px !important; padding-top: 0; border-top: 0; }