/* PRISM project page. Plain type, white page, video first. No external fonts or UI libraries. */
:root{
  --bg:#fff;
  --ink:#141414;
  --text:#2b2b2b;
  --muted:#707070;
  --faint:#a6a6a3;
  --line:#e8e8e5;
  --soft:#f4f4f2;
  --gold:#d9a93a;
  --real:#2f7a4a;
  --sans:ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI","Helvetica Neue",Arial,sans-serif;
  --serif:"Iowan Old Style","Palatino Linotype",Georgia,serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}

/* Base */
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:28px}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.65 var(--sans);-webkit-font-smoothing:antialiased}
h1,h2,h3,h4,p,figure,ul{margin:0}
a{color:inherit;text-decoration:none}
a:hover{text-decoration:underline;text-underline-offset:3px}
button{font:inherit;color:inherit;cursor:pointer;-webkit-tap-highlight-color:transparent}
img,video{display:block;max-width:100%}
video{width:100%;height:100%;object-fit:contain;background:var(--soft)}
[hidden]{display:none!important}
:focus-visible{outline:2px solid var(--ink);outline-offset:3px}
:focus:not(:focus-visible){outline:none}
.skip-link{position:fixed;left:12px;top:-60px;z-index:100;padding:10px 14px;border-radius:6px;background:var(--ink);color:#fff}
.skip-link:focus{top:12px}

/* Layout */
.section-shell{max-width:1192px;margin:0 auto;padding:0 36px}
@media(min-width:1450px){.section-shell{max-width:1232px}}
.section-space{padding-top:96px;padding-bottom:96px}
/* Section label: a short rule and muted gold so every section reads as a new start. */
.kicker{display:flex;align-items:center;gap:10px;margin-bottom:12px;font-size:13px;font-weight:600;color:#8a6a1f}
.kicker:before{content:"";width:20px;height:2px;border-radius:1px;background:var(--gold)}
/* Alternating bands mark section boundaries. */
.band{background:#f6f6f3;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.band .citation-block pre{background:#fff;border:1px solid var(--line)}
.band .video-frame,.band .pipeline-frame{background:#ecece8}
.section-title{font-size:clamp(26px,2.8vw,34px);font-weight:600;line-height:1.2;letter-spacing:-.012em;color:var(--ink)}
.section-title.solo{margin-bottom:28px}
.section-intro{max-width:720px;margin-top:10px;font-size:16px;color:var(--muted)}
.section-heading-row{display:flex;justify-content:space-between;align-items:flex-end;gap:24px;margin-bottom:28px}

/* Buttons */
.controls{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;height:40px;padding:0 18px;border:1px solid #d6d6d2;border-radius:999px;background:var(--bg);color:var(--ink);font-size:14px;font-weight:500;line-height:1;white-space:nowrap;transition:border-color .15s}
.button:hover:not(:disabled){border-color:var(--ink);text-decoration:none}
.button:disabled{cursor:default;opacity:.55}
.button-small{height:32px;padding:0 14px;font-size:13px}
.btn-icon{flex:0 0 auto;width:16px;height:16px;fill:currentColor}

/* Hero */
.hero{padding-top:88px;text-align:center}
.hero-kicker{justify-content:center;margin-bottom:18px;color:var(--muted);font-weight:500}
.hero-kicker:before{display:none}
.hero-kicker{margin-bottom:22px;text-decoration:underline;text-decoration-color:var(--gold);text-decoration-thickness:1.5px;text-underline-offset:8px}
.hero-wordmark{display:flex;align-items:center;justify-content:center;gap:.18em;font-size:64px;font-weight:700;line-height:1;letter-spacing:-.02em;color:var(--ink)}
.prism-mark{display:inline-block;flex:0 0 auto;width:.74em;height:.8em;clip-path:polygon(45% 0,100% 100%,0 100%);background:linear-gradient(77deg,#d4a72c 0 48%,#eecd6d 48% 64%,#768264 64%)}
h1{max-width:880px;margin:24px auto 0;font-size:clamp(26px,3.3vw,38px);font-weight:600;line-height:1.2;letter-spacing:-.012em;color:var(--ink)}
.title-for{font-family:var(--serif);font-style:italic;font-weight:400;font-size:.72em;color:var(--muted);letter-spacing:0}
.mobile-break{display:none}
.hero-deck{margin-top:18px;font-size:19px;color:var(--text)}
.venue{display:flex;align-items:center;justify-content:center;gap:14px;margin-top:22px;color:#bc5400;font-size:18px;font-weight:600}
.venue img{flex:0 1 auto;width:clamp(110px,12vw,171px);height:auto}
.venue span{min-width:0}
.authors{display:flex;flex-direction:column;align-items:center;gap:6px;margin-top:30px;font-size:16px;color:var(--ink)}
.author-row{display:flex;flex-wrap:wrap;justify-content:center;gap:4px 26px}
.author-row a{white-space:nowrap}
.authors sup{margin-left:1px;font-size:10px;color:var(--muted)}
.affiliations{display:flex;flex-wrap:wrap;justify-content:center;gap:4px 22px;margin-top:14px;font-size:14px;color:var(--muted)}
.affiliations sup{margin-right:2px;font-size:9px}
.affiliation-note{white-space:nowrap}
.hero-actions{display:flex;flex-wrap:wrap;justify-content:center;gap:10px;margin-top:28px}
.hero-film{position:relative;aspect-ratio:16/9;margin-top:48px;border-radius:12px;overflow:hidden;background:#111}
.hero-film video{object-fit:cover;background:#111}
.film-control{position:absolute;right:12px;bottom:12px;height:28px;padding:0 12px;border:0;border-radius:999px;background:rgba(0,0,0,.45);color:#fff;font-size:12px}
.film-control:hover{background:rgba(0,0,0,.65)}
.number-strip{display:grid;grid-template-columns:repeat(4,1fr);margin-top:36px}
.number-strip strong{display:block;font-size:28px;font-weight:600;line-height:1.1;color:var(--ink);font-variant-numeric:tabular-nums}
.number-strip span{display:block;margin-top:4px;font-size:13px;color:var(--muted)}

/* Deployment facts */
.fact-chips{display:grid;grid-template-columns:repeat(3,1fr);gap:28px;margin-bottom:40px;padding:22px 0;list-style:none;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.fact-chips li{display:flex;align-items:flex-start;gap:12px;min-width:0}
.fact-icon{flex:0 0 22px;margin-top:1px;color:var(--ink)}
.fact-icon svg{width:22px;height:22px;fill:none;stroke:currentColor;stroke-width:1.6;stroke-linecap:round;stroke-linejoin:round}
.fact-text{display:flex;flex-direction:column;gap:2px}
.fact-text strong{font-size:15px;font-weight:600;line-height:1.35;color:var(--ink)}
.fact-text small{font-size:13px;color:var(--muted)}

/* Tabs: results categories and animation stages share one look. */
.result-tabs,.multiply-steps{display:flex;flex-wrap:wrap;gap:4px 24px;border-bottom:1px solid var(--line)}
.result-tabs [role=tab],.multiply-step{margin-bottom:-1px;padding:10px 0;border:0;border-bottom:2px solid transparent;background:none;color:var(--muted);font-size:14px;font-weight:500;white-space:nowrap}
.result-tabs [role=tab]:hover,.multiply-step:hover{color:var(--ink)}
.result-tabs [aria-selected=true],.multiply-step[aria-pressed=true]{border-bottom-color:var(--ink);color:var(--ink)}
.tab-count{font-weight:400;color:var(--faint)}
.multiply-step strong{margin-right:3px;font-weight:600}

/* Results gallery */
.gallery-heading h3{margin:26px 0 16px;font-size:16px;font-weight:600;color:var(--ink)}
.result-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:28px 22px}
.result-grid>.result-card:last-child:nth-child(odd){grid-column:1/-1;justify-self:center;width:calc(50% - 11px)}
.video-frame{position:relative;aspect-ratio:16/9;border-radius:8px;overflow:hidden;background:var(--soft)}
.result-card figcaption{display:flex;justify-content:space-between;gap:16px;padding-top:10px}
.result-card h4{margin:0;font-size:15px;font-weight:600;line-height:1.4;color:var(--ink)}
.result-card figcaption p{font-size:13px;color:var(--muted)}
.clip-index{padding-top:2px;font-size:12px;color:var(--faint);font-variant-numeric:tabular-nums}
.speed-badge,.corner-label{position:absolute;top:8px;left:8px;z-index:2;padding:2px 7px;border-radius:4px;background:rgba(0,0,0,.55);color:#fff;font-size:11px;font-weight:500;pointer-events:none}
.expand-video{position:absolute;inset:0;z-index:1;border:0;background:transparent;cursor:zoom-in}

/* Which video is real? */
.quiz-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
.quiz-tile{position:relative;aspect-ratio:16/9;padding:0;border:0;border-radius:8px;overflow:hidden;background:var(--soft);box-shadow:0 0 0 2px transparent;transition:box-shadow .15s}
.quiz-tile:hover{box-shadow:0 0 0 2px #cfcfcb}
.quiz-tile.selected{box-shadow:0 0 0 2px var(--ink)}
.quiz-tile.is-real{box-shadow:0 0 0 3px var(--real)}
/* The source clips gain an answer-colored border after the opening frames; crop every tile equally. */
.quiz-tile video{object-fit:contain;transform:scale(1.1)}
.quiz-number{position:absolute;top:8px;left:10px;z-index:2;color:#fff;font-size:13px;font-weight:600;text-shadow:0 1px 3px rgba(0,0,0,.5)}
.quiz-answer{display:none;position:absolute;left:8px;bottom:8px;z-index:2;padding:3px 8px;border-radius:4px;background:rgba(0,0,0,.6);color:#fff;font-size:12px;font-weight:500}
.quiz-tile.revealed .quiz-answer{display:block}
.quiz-tile.is-real .quiz-answer{background:var(--real)}
.quiz-feedback{margin-top:18px;font-size:15px;color:var(--muted)}
.quiz-feedback strong{display:block;margin-bottom:2px;font-weight:600;color:var(--ink)}
.sample-explorer{margin-top:48px;padding-top:32px;border-top:1px solid var(--line)}
.sample-explorer-head h3{font-size:18px;font-weight:600;color:var(--ink)}
.sample-explorer-head p{margin-top:4px;font-size:14px;color:var(--muted)}
.sample-options{display:flex;flex-wrap:wrap;gap:8px;margin:18px 0 20px}
.sample-option{padding:5px 13px;border:1px solid #d6d6d2;border-radius:999px;background:var(--bg);color:var(--muted);font-size:13px}
.sample-option:hover{border-color:var(--ink);color:var(--ink)}
.sample-option[aria-pressed=true]{border-color:var(--ink);background:var(--ink);color:#fff}
.sample-pair{display:grid;grid-template-columns:1fr 28px 1fr;gap:12px;align-items:start}
.sample-pair figure{min-width:0}
.sample-pair video{object-fit:cover}
.sample-pair figcaption{padding-top:8px;font-size:13px;color:var(--muted)}
.pair-arrow{align-self:center;margin-top:-24px;text-align:center;color:var(--faint);font-size:20px}

/* The idea */
.editorial-grid{display:grid;grid-template-columns:1fr 1fr;gap:48px;align-items:end}
.lead{font-size:18px;line-height:1.6;color:var(--text)}
.idea-summary{margin-top:8px;font-size:16px;color:var(--muted)}

/* One video to 256, then objects, kinematics and sim-to-real.
   A 2×2 grid zooms out from the source tile; one clip continues through the video wall and robot references. */
.multiply{margin-top:44px}
.multiply-stage{position:relative;aspect-ratio:16/9;overflow:hidden;border-radius:12px;background:#111}
.multiply-viewport{position:absolute;inset:0}
.multiply-grid{position:absolute;inset:0;display:grid;grid-template-columns:repeat(2,minmax(0,1fr));grid-template-rows:repeat(2,minmax(0,1fr));background:#fff;transform:scale(2);transform-origin:0 0;will-change:transform;transition:transform 1.9s cubic-bezier(.7,0,.2,1),opacity .35s ease}
.multiply-stage.instant .multiply-grid,.multiply-stage.instant .multiply-layer{transition:none}
.multiply-stage.is-resetting .multiply-grid{opacity:0}
.multiply-tile{position:relative;min-width:0;min-height:0;overflow:hidden;border:.25px solid rgba(255,255,255,.9);background:#222}
.multiply-tile video,.multiply-tile img{width:100%;height:100%;object-fit:cover;background:#222}
.multiply-tile img{opacity:.9}
.multiply-tile video{transform:scale(1.1)}
.multiply-tile.is-seed{z-index:2}
.multiply-tile.is-seed:after{content:"";position:absolute;inset:0;box-shadow:inset 0 0 0 .2px var(--gold);pointer-events:none}
.multiply-layer{position:absolute;inset:0;z-index:2;width:100%;height:100%;object-fit:cover;opacity:0;transition:opacity .9s ease;pointer-events:none}
.multiply-stage[data-phase="256"] .multiply-layer,
.multiply-stage[data-phase="objects"] .multiply-layer,
.multiply-stage[data-phase="motion"] .multiply-layer,
.multiply-stage[data-phase="sim2real"] .multiply-layer{opacity:1}
.multiply-stage.is-resetting .multiply-layer{opacity:0;transition-duration:.4s}
.multiply-overlay{position:absolute;left:16px;bottom:14px;z-index:3;display:flex;align-items:baseline;gap:10px;padding:6px 12px;border-radius:6px;background:rgba(0,0,0,.5);color:#fff;pointer-events:none;transition:opacity .3s}
.multiply-stage.is-resetting .multiply-overlay{opacity:0}
.multiply-count{font-size:26px;font-weight:600;line-height:1;font-variant-numeric:tabular-nums}
.multiply-label{font-size:13px;font-weight:500}
.multiply-overlay.no-count .multiply-count{display:none}
/* The Twitter clips carry their own labels; keep the stage name in the controls below. */
.multiply-stage[data-phase="256"] .multiply-overlay,
.multiply-stage[data-phase="objects"] .multiply-overlay,
.multiply-stage[data-phase="motion"] .multiply-overlay,
.multiply-stage[data-phase="sim2real"] .multiply-overlay{opacity:0}
.multiply-foot{margin-top:14px}

/* Method: input video, reconstruction, retargeted motion, then the paper figure. */
.pipeline{display:grid;grid-template-columns:1fr 28px 1fr 28px 1fr;gap:12px;align-items:center}
.pipeline-step,.pipeline-arrow{opacity:0;transform:translateY(8px);transition:opacity .6s ease,transform .6s ease;transition-delay:calc(var(--i) * .2s)}
.pipeline.is-in .pipeline-step,.pipeline.is-in .pipeline-arrow{opacity:1;transform:none}
.pipeline-frame{aspect-ratio:1/1;border-radius:8px;overflow:hidden;background:var(--soft)}
.pipeline-frame video{object-fit:cover}
/* The input clip faces the other way: mirror it, and zoom about the feet so the person matches the mesh and robot. */
.pipeline-step:first-child video{object-position:50% 71%;transform:scale(-1.14,1.14);transform-origin:50% 80%}
.pipeline-step figcaption{margin-top:10px;font-size:14px;font-weight:500;color:var(--ink);text-align:center}
.pipeline-arrow{margin-top:-28px;text-align:center;color:var(--faint);font-size:20px}
.method-figure{margin-top:56px;padding:24px 24px 20px;border:1px solid var(--line);border-radius:12px;background:#fff}
.method-figure img{width:100%;height:auto}
.method-figure figcaption{max-width:760px;margin-top:14px;font-size:14px;color:var(--muted)}
.method-figure figcaption strong{font-weight:600;color:var(--ink)}

/* BibTeX and acknowledgements */
.closing-notes+.closing-notes{padding-top:0;border-top:0}
.closing-notes:has(+.closing-notes){border-bottom:0}
.citation-block pre{margin:0;padding:18px 20px;border-radius:8px;background:var(--soft);color:var(--text);font:13px/1.7 var(--mono);white-space:pre-wrap;overflow-wrap:anywhere}
.citation-block .controls{margin-top:12px}
#copy-status{font-size:13px;color:var(--muted)}
.ack-block p{font-size:15px;line-height:1.75;color:var(--text)}
.ack-block a{text-decoration:underline;text-decoration-color:#bdbdb8;text-underline-offset:3px}

/* Enlarged video */
dialog{max-height:92vh;padding:20px;border:0;border-radius:12px;background:var(--bg);color:var(--text);box-shadow:0 20px 60px rgba(0,0,0,.25)}
dialog::backdrop{background:rgba(0,0,0,.6)}
.video-dialog{width:min(1100px,94vw)}
.dialog-head{display:flex;align-items:center;justify-content:space-between;gap:16px;margin-bottom:14px}
.dialog-head h2{font-size:18px;font-weight:600;color:var(--ink)}
.dialog-close{display:grid;place-items:center;width:32px;height:32px;border:1px solid var(--line);border-radius:50%;background:none;font-size:20px;line-height:1}
.video-dialog video{max-height:72vh;border-radius:6px;background:#000}
.video-dialog>p{margin-top:10px;font-size:13px;color:var(--muted)}

/* Messages */
.media-error{position:absolute;inset:0;z-index:5;display:grid;place-items:center;padding:16px;background:var(--soft);color:var(--muted);font-size:13px;text-align:center}
.noscript-message{padding:16px;background:var(--soft);font-size:14px;text-align:center}

/* Section rail, only where the margin can hold it. */
.side-nav{display:none}
@media(min-width:1440px){
  .side-nav{position:fixed;left:24px;top:50%;z-index:20;display:flex;flex-direction:column;gap:12px;transform:translateY(-50%)}
  .side-nav a{display:flex;align-items:center;gap:10px;font-size:12px;color:var(--faint);transition:color .15s}
  .side-nav a:before{content:"";width:8px;height:1px;background:currentColor;transition:width .15s}
  .side-nav a:hover{color:var(--ink);text-decoration:none}
  .side-nav a.active{color:var(--ink);font-weight:600}
  .side-nav a.active:before{width:18px}
}

@media(max-width:760px){
  .section-shell{padding:0 20px}
  .section-space{padding-top:64px;padding-bottom:64px}
  .section-heading-row{flex-direction:column;align-items:flex-start;gap:14px;margin-bottom:22px}
  .section-title{font-size:24px}
  .section-intro{font-size:15px}
  .hero{padding-top:56px}
  .hero-wordmark{font-size:46px}
  h1{margin-top:18px;font-size:24px}
  .desktop-break{display:none}
  .hero-deck{font-size:16px}
  .venue{gap:10px;margin-top:18px;font-size:14px}
  .venue img{width:clamp(96px,30vw,120px)}
  .authors{margin-top:24px;font-size:14px}
  .author-row{gap:2px 16px}
  .affiliations{gap:2px 14px;font-size:12.5px}
  .hero-actions{gap:8px;margin-top:22px}
  .button{height:36px;padding:0 14px;font-size:13px}
  .hero-film{margin-top:32px;border-radius:8px}
  .number-strip{grid-template-columns:repeat(2,1fr);gap:18px 0}
  .number-strip strong{font-size:24px}
  .fact-chips{grid-template-columns:1fr;gap:14px;margin-bottom:28px;padding:18px 0}
  .result-tabs,.multiply-steps{flex-wrap:nowrap;gap:0 20px;overflow-x:auto;scrollbar-width:none}
  .result-tabs::-webkit-scrollbar,.multiply-steps::-webkit-scrollbar{display:none}
  .result-grid{grid-template-columns:1fr;gap:22px}
  .result-grid>.result-card:last-child:nth-child(odd){grid-column:auto;width:auto}
  .quiz-grid{gap:8px}
  .quiz-number{top:5px;left:7px;font-size:11px}
  .quiz-answer{left:5px;bottom:5px;padding:2px 6px;font-size:10px}
  .sample-pair{grid-template-columns:1fr 14px 1fr;gap:6px}
  .pair-arrow{font-size:14px}
  .editorial-grid{grid-template-columns:1fr;gap:16px}
  .lead{font-size:16px}
  .multiply{margin-top:28px}
  .multiply-stage{border-radius:8px}
  .multiply-overlay{left:10px;bottom:10px;gap:7px;padding:4px 9px}
  .multiply-count{font-size:20px}
  .multiply-label{font-size:11px}
  .pipeline{grid-template-columns:1fr;gap:8px}
  .pipeline-frame{aspect-ratio:5/4}
  .pipeline-arrow,.pipeline.is-in .pipeline-arrow{margin-top:0;transform:rotate(90deg)}
  .method-figure{margin-top:36px;padding:12px;border-radius:9px}
  .citation-block pre{padding:14px;font-size:11.5px}
  dialog{padding:14px}
}
@media(max-width:440px){
  .mobile-break{display:block}
  .hero-wordmark{font-size:40px}
}
@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*:before,*:after{transition:none!important;animation:none!important}
  .pipeline-step,.pipeline-arrow{opacity:1;transform:none}
}

.hero-deck{max-width:840px;margin-left:auto;margin-right:auto;line-height:1.55}