:root{
  --ink:#1f2a36;--text:#3a4654;--muted:#6b7785;--faint:#98a2ad;
  --line:#e6e9ee;--soft:#f6f7f9;--tint:#fbf4f1;
  --accent:#b4695a;--accent-d:#94503f;--accent-l:#f3e2dc;
  --slate:#4d6276;--good:#3f7a68;
  --sans:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Hiragino Sans GB","Microsoft YaHei","Noto Sans CJK SC",Arial,sans-serif;
  --mono:"SF Mono",ui-monospace,Menlo,Consolas,monospace;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:72px}
body{margin:0;background:#fff;color:var(--text);font-family:var(--sans);font-size:17px;line-height:1.72;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
html[data-lang="zh"] body{line-height:1.85;letter-spacing:.01em}
html[data-lang="en"] [data-l="zh"],html[data-lang="zh"] [data-l="en"]{display:none!important}
main{max-width:1080px;padding:0 36px;margin:auto}
a{color:inherit;text-decoration:none}
a:hover{color:var(--accent)}
a:focus-visible,button:focus-visible,summary:focus-visible{outline:2px solid var(--accent);outline-offset:4px;border-radius:4px}
button{font:inherit;color:inherit}
code{font-family:var(--mono);font-size:.86em;background:var(--soft);border:1px solid var(--line);border-radius:4px;padding:1px 5px}
strong{color:var(--ink);font-weight:620}

/* top bar */
.topbar{position:sticky;top:0;z-index:20;background:rgba(255,255,255,.82);backdrop-filter:saturate(1.6) blur(12px);-webkit-backdrop-filter:saturate(1.6) blur(12px);border-bottom:1px solid transparent;transition:border-color .2s,box-shadow .2s}
.topbar.scrolled{border-bottom-color:var(--line);box-shadow:0 1px 12px rgba(31,42,54,.04)}
.topbar-inner{max-width:1080px;margin:auto;padding:0 36px;height:56px;display:flex;align-items:center;gap:28px}
.brand{font-weight:700;letter-spacing:.02em;color:var(--ink);font-size:15px;opacity:0;transform:translateY(4px);transition:opacity .25s,transform .25s;pointer-events:none}
.topbar.scrolled .brand{opacity:1;transform:none;pointer-events:auto}
.brand span{color:var(--accent);margin:0 2px}
.nav-links{display:flex;gap:22px;margin-left:auto;font-size:14px;color:var(--muted)}
.nav-links a{position:relative;padding:4px 0}
.nav-links a.active{color:var(--ink)}
.nav-links a.active::after{content:"";position:absolute;left:0;right:0;bottom:-2px;height:2px;border-radius:2px;background:var(--accent)}
.lang-switch{display:inline-flex;border:1px solid var(--line);border-radius:999px;padding:2px;background:#fff}
.lang-switch button{border:0;background:transparent;padding:3px 11px;border-radius:999px;font-size:12.5px;font-weight:560;color:var(--muted);cursor:pointer;transition:background .15s,color .15s}
html[data-lang="en"] .lang-switch [data-set-lang="en"],html[data-lang="zh"] .lang-switch [data-set-lang="zh"]{background:var(--ink);color:#fff}

/* hero */
header.hero{text-align:center;padding:56px 0 30px}
.project-name{font-size:13px;letter-spacing:.3em;font-weight:650;color:var(--faint);margin:0 0 22px}
.project-name span{color:var(--accent);margin:0 3px}
h1{font-size:clamp(30px,3.6vw,46px);line-height:1.2;letter-spacing:-.032em;font-weight:720;margin:0 auto 26px;color:var(--ink);max-width:900px}
h1 span{background:linear-gradient(100deg,#b4695a,#c98a5e);-webkit-background-clip:text;background-clip:text;color:transparent}
h1.zh-title{letter-spacing:.01em;line-height:1.35;margin-bottom:10px}
.subtitle{font-size:14px;color:var(--faint);margin:0 auto 24px;max-width:720px;line-height:1.5;font-style:italic}
.authors{max-width:900px;margin:auto;display:flex;justify-content:center;gap:4px 18px;flex-wrap:wrap;color:var(--slate);font-size:17.5px}
.author{white-space:nowrap}
sup{font-size:.62em;line-height:0;vertical-align:super;margin-left:2px;color:var(--faint)}
.affiliations{font-size:13.5px;color:var(--muted);margin:16px auto 4px;max-width:820px;display:flex;flex-wrap:wrap;gap:2px 20px;justify-content:center}
.correspondence{font-size:12.5px;color:var(--faint);margin:6px 0 24px}
.links{display:flex;justify-content:center;gap:10px;flex-wrap:wrap}
.pill{display:inline-flex;align-items:center;gap:7px;border-radius:999px;padding:8px 18px;font-size:14px;font-weight:560;background:var(--ink);color:#fff;border:1px solid var(--ink);transition:background .18s,color .18s,border-color .18s,transform .18s}
.pill:hover{background:var(--accent);border-color:var(--accent);color:#fff;transform:translateY(-1px)}
.pill-ghost{background:#fff;color:var(--ink);border-color:#d6dbe1}
.pill-ghost:hover{background:var(--tint);color:var(--accent-d);border-color:var(--accent-l)}
.pill svg{width:16px;height:16px;stroke:currentColor;stroke-width:1.7;fill:none;stroke-linejoin:round;stroke-linecap:round}

/* stats */
section.stats{display:grid;grid-template-columns:1.35fr 1fr 1fr;gap:0;padding:8px 0 22px;margin:8px 0 0;border-top:1px solid var(--line);border-bottom:1px solid var(--line)}
.stat{padding:20px 26px;text-align:center}
.stat+.stat{border-left:1px solid var(--line)}
.stat-value{font-size:30px;font-weight:700;letter-spacing:-.03em;color:var(--ink);margin:0;font-variant-numeric:tabular-nums;white-space:nowrap}
.stat-value small{font-size:.6em;font-weight:600;color:var(--muted);margin-left:1px}
.stat-value i{font-style:normal;color:var(--accent);margin:0 9px;font-weight:500}
.stat-label{font-size:13px;line-height:1.55;color:var(--muted);margin:6px auto 0;max-width:280px}

/* sections */
section{padding:54px 0}
section.overview{padding:30px 0 26px}
.takeaway{font-size:25px;line-height:1.45;text-align:center;font-weight:560;margin:6px 0 26px;letter-spacing:-.02em;color:var(--ink)}
.takeaway em{font-style:normal;color:var(--accent)}
h2{font-size:clamp(25px,2.6vw,31px);line-height:1.3;letter-spacing:-.025em;font-weight:700;color:var(--ink);margin:0 0 12px}
h3{color:var(--ink)}
.section-heading{text-align:center;max-width:780px;margin:0 auto 30px}
.eyebrow{display:inline-block;font-size:11.5px;letter-spacing:.2em;font-weight:680;color:var(--accent);margin:0 0 10px}
.section-intro{color:var(--muted);font-size:16.5px;margin:0 auto}
.caption,figcaption{font-size:13.5px;line-height:1.65;color:var(--muted);text-align:center;max-width:820px;margin:14px auto 0}
figure{margin:22px 0 0}
.image-button{display:block;width:100%;padding:0;background:transparent;border:0;cursor:zoom-in;border-radius:10px;overflow:hidden}
.image-button img{display:block;width:100%;height:auto;transition:transform .35s ease}
.image-button:hover img{transform:scale(1.008)}
.overview figure .image-button,#method figure .image-button,.robot-section figure .image-button{border:1px solid var(--line);box-shadow:0 1px 2px rgba(31,42,54,.04),0 8px 28px rgba(31,42,54,.06)}

/* abstract */
.abstract{max-width:820px;margin:0 auto;padding:40px 0 40px}
.abstract h2{text-align:center;margin-bottom:18px}
.abstract p{margin:0 0 14px;text-align:justify;hyphens:auto}
html[data-lang="zh"] .abstract p{text-align:justify}

/* reasoning case */
.reasoning-section{background:linear-gradient(180deg,#fff, var(--tint) 18%, var(--tint) 82%, #fff);margin:0 -36px;padding:60px 36px}
.reasoning-feature{display:grid;grid-template-columns:1fr 1.05fr;gap:0;background:#fff;border:1px solid #eedfd9;border-radius:16px;box-shadow:0 10px 40px rgba(148,80,63,.07);overflow:hidden}
.contact-evidence,.agent-interpretation{padding:30px 32px}
.agent-interpretation{border-left:1px solid #f0e6e2}
.step-label{display:flex;align-items:center;gap:10px;font-size:12px;font-weight:650;letter-spacing:.04em;color:var(--muted);margin:0 0 18px;text-transform:uppercase}
html[data-lang="zh"] .step-label{text-transform:none;letter-spacing:.06em}
.step-label>span{display:inline-grid;place-items:center;width:24px;height:24px;border-radius:50%;background:var(--accent-l);color:var(--accent-d);font-size:11px;font-variant-numeric:tabular-nums;font-weight:700;letter-spacing:0}
.step-label b{font-weight:650}
.scene-context{display:flex;gap:18px;align-items:center;margin-bottom:20px}
.scene-context>img{width:150px;height:auto;border-radius:8px;border:1px solid var(--line)}
.scene-context strong{font-size:17px;font-weight:650}
.scene-context p{font-size:12.5px;line-height:1.75;color:var(--muted);margin:4px 0}
.sensor-figure{margin:0}
.sensor-figure figcaption{text-align:left;margin-top:8px;font-size:12.5px}
.sensor-figure .image-button{border-radius:8px}
details summary{cursor:pointer;list-style:none}
details summary::-webkit-details-marker{display:none}
details summary::before{content:"";display:inline-block;width:6px;height:6px;border-right:1.5px solid currentColor;border-bottom:1.5px solid currentColor;transform:rotate(-45deg);margin:0 9px 2px 1px;transition:transform .2s}
details[open]>summary::before{transform:rotate(45deg)}
.other-sensor{margin-top:12px}
.other-sensor summary{font-size:12.5px;color:var(--slate)}
.other-sensor figure{margin-top:12px}
.agent-interpretation blockquote{margin:0;font-size:22px;line-height:1.55;letter-spacing:-.012em;color:var(--ink);position:relative}
.agent-interpretation blockquote p{margin:0 0 12px}
mark{background:linear-gradient(transparent 55%,#f6dcd3 55%);color:inherit;padding:0 1px;box-decoration-break:clone;-webkit-box-decoration-break:clone}
.quote-translation{font-size:16px;line-height:1.75;color:var(--text);margin:4px 0 0;padding:10px 14px;background:var(--soft);border-radius:8px}
.quote-source{font-size:11.5px;color:var(--faint);margin:12px 0 22px}
.execution-outcome{border-top:1px dashed #e8dcd7;padding-top:18px}
.execution-outcome .step-label{margin-bottom:10px}
.action-title{font-size:20px;font-weight:650;letter-spacing:-.015em;margin:0;color:var(--slate)}
.action-title i{font-style:normal;color:var(--faint);font-weight:400;padding:0 5px}
.outcome-note{font-size:13.5px;color:var(--muted);margin:4px 0 12px}
.native-result{display:inline-block;font-size:12.5px;font-weight:600;color:var(--good);background:#e9f3ef;border-radius:999px;padding:3px 12px}
.reasoning-note{color:var(--muted);font-size:12.5px;text-align:center;margin:18px 0 6px}
.trace-details{text-align:center;margin-top:6px}
.trace-details>summary{display:inline-block;font-size:14px;font-weight:560;color:var(--accent-d);padding:7px 16px;border-radius:999px;border:1px solid var(--accent-l);background:#fff;transition:background .15s}
.trace-details>summary:hover{background:var(--tint)}
.trace-details figure{text-align:left;background:#fff;border-radius:12px;padding:12px;border:1px solid var(--line)}

/* method steps */
.steps{list-style:none;padding:0;margin:0 0 6px;display:grid;grid-template-columns:repeat(3,1fr);gap:18px;counter-reset:s}
.steps li{position:relative;border:1px solid var(--line);border-radius:14px;padding:22px 22px 18px;background:#fff;transition:border-color .2s,box-shadow .2s}
.steps li:hover{border-color:var(--accent-l);box-shadow:0 8px 26px rgba(31,42,54,.06)}
.step-num{display:inline-grid;place-items:center;width:28px;height:28px;border-radius:8px;background:var(--ink);color:#fff;font-size:13px;font-weight:700}
.steps h3{font-size:17px;margin:12px 0 6px;letter-spacing:-.01em}
.steps p{font-size:14.5px;line-height:1.7;color:var(--muted);margin:0}
#method figure{margin-top:28px}

/* tables */
.table-scroll{overflow-x:auto;border:1px solid var(--line);border-radius:14px}
table{width:100%;border-collapse:collapse;font-variant-numeric:tabular-nums;font-size:15.5px;min-width:720px}
caption{caption-side:bottom;font-size:12.5px;color:var(--muted);padding:12px 16px;text-align:left;border-top:1px solid var(--line);background:var(--soft)}
th,td{padding:13px 16px;text-align:center}
thead th{font-size:13.5px;font-weight:650;color:var(--ink);background:var(--soft);vertical-align:bottom;line-height:1.35;border-bottom:1px solid var(--line)}
thead th small{display:block;font-size:11.5px;font-weight:500;color:var(--muted);margin-top:3px}
thead th:first-child,tbody th{text-align:left}
tbody th{font-weight:600;color:var(--ink);white-space:nowrap}
tbody th small{display:block;font-size:11.5px;font-weight:450;color:var(--faint);line-height:1.3}
tbody tr+tr th,tbody tr+tr td{border-top:1px solid #f0f2f5}
td{color:var(--muted)}
td strong{color:var(--ink)}
.ours{background:var(--tint)}
thead th.ours{background:#f5e6e0;color:var(--accent-d)}
td.ours{color:var(--accent-d)}
td.ours strong{color:var(--accent-d);font-weight:720}
.delta{font-size:13.5px;font-weight:620}
.delta.up{color:var(--good)}
.delta.down{color:var(--faint)}
tr.average th,tr.average td{border-top:1.5px solid #dfe3e8!important;font-weight:650}
tr.average td{color:var(--text)}

/* ablations */
.sub-heading{font-size:21px;letter-spacing:-.02em;text-align:center;margin:54px 0 6px}
.sub-intro{text-align:center;color:var(--muted);font-size:14.5px;margin:0 auto 22px;max-width:720px}
.ablations{display:grid;grid-template-columns:1.2fr 1fr 1fr;gap:18px;align-items:start}
.ablation{border:1px solid var(--line);border-radius:14px;padding:20px 20px 16px}
.ablation h4{margin:0 0 14px;font-size:15.5px;color:var(--ink);display:flex;justify-content:space-between;align-items:baseline;gap:8px}
.ablation h4 small{font-size:11.5px;font-weight:550;color:var(--faint);letter-spacing:.02em}
.ablation>p{font-size:13.5px;line-height:1.65;color:var(--muted);margin:14px 0 0}
.bars{display:grid;gap:8px}
.bar-head,.bar-row{display:grid;grid-template-columns:104px 1fr;gap:10px;align-items:center}
.two-col .bar-head,.two-col .bar-row{grid-template-columns:96px 1fr 1fr}
.bar-head{font-size:11px;color:var(--faint);font-weight:600;letter-spacing:.02em}
.bar-label{font-size:12.5px;color:var(--text);line-height:1.3}
.bar{position:relative;height:22px;border-radius:5px;background:var(--soft)}
.bar::before{content:"";position:absolute;inset:0 auto 0 0;width:calc((100% - 24px) * var(--v) / 36);min-width:3px;border-radius:5px;background:#c9d2db;transition:width .9s cubic-bezier(.2,.7,.2,1)}
.bar.hi::before{background:linear-gradient(90deg,#c98a6e,var(--accent))}
.bar b{position:absolute;top:50%;transform:translateY(-50%);left:calc((100% - 24px) * var(--v) / 36 + 5px);font-size:12px;font-weight:650;color:var(--text);font-variant-numeric:tabular-nums}
.bar.hi b{color:var(--accent-d)}
.js .bars:not(.in) .bar::before{width:0}
.mini-details{margin-top:12px}
.mini-details summary{font-size:12.5px;color:var(--slate)}
.mini-details figure{margin-top:10px}
.mini-details figcaption{text-align:left;font-size:12px}

/* real robot */
.video-wrap{position:relative;max-width:820px;margin:0 auto;border-radius:14px;overflow:hidden;background:#0d1117;box-shadow:0 12px 40px rgba(31,42,54,.12)}
.video-wrap video{display:block;width:100%;height:auto}
.video-speed{position:absolute;top:12px;right:12px;font-size:11.5px;font-weight:650;color:#fff;background:rgba(0,0,0,.5);border-radius:999px;padding:2px 10px;backdrop-filter:blur(6px);pointer-events:none}
.robot-section figure{margin-top:34px}

/* citation */
.citation{max-width:860px;margin:0 auto}
.citation h2{text-align:center;margin-bottom:18px}
.bibtex{position:relative;background:#1d2530;border-radius:12px;color:#d7dee6}
.bibtex pre{margin:0;padding:20px 22px;overflow-x:auto;font-size:13px;line-height:1.65}
.bibtex code{background:none;border:0;padding:0;font-size:inherit;color:inherit;white-space:pre-wrap;word-break:break-word}
.copy-btn{position:absolute;top:10px;right:10px;border:1px solid rgba(255,255,255,.18);background:rgba(255,255,255,.06);color:#e6ebf0;border-radius:6px;font-size:12px;padding:3px 10px;cursor:pointer}
.copy-btn:hover{background:rgba(255,255,255,.14)}
.copy-btn.done{border-color:#7fbfa9;color:#9fd8c3}
.text-link{display:inline-block;margin-top:16px;font-size:14.5px;font-weight:560;color:var(--accent-d)}
.citation .text-link{display:block;text-align:center}

footer{border-top:1px solid var(--line);margin-top:40px;padding:26px 0 46px;font-size:12.5px;color:var(--faint);display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap}
footer a{color:var(--muted);border-bottom:1px solid var(--line)}

/* lightbox */
dialog{border:0;padding:0;max-width:min(1400px,94vw);max-height:94vh;border-radius:14px;background:#fff;box-shadow:0 30px 80px rgba(0,0,0,.3)}
dialog::backdrop{background:rgba(17,24,32,.72);backdrop-filter:blur(3px)}
dialog img{display:block;max-width:100%;max-height:82vh;margin:auto}
dialog p{font-size:13.5px;color:var(--muted);margin:0;padding:12px 22px 16px;text-align:center}
dialog .close{position:absolute;top:8px;right:10px;border:0;background:rgba(255,255,255,.9);width:34px;height:34px;border-radius:50%;font-size:22px;line-height:1;cursor:pointer;color:var(--ink)}

/* reveal */
.js .reveal{opacity:0;transform:translateY(14px);transition:opacity .6s ease,transform .6s ease}
.js .reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}.js .reveal{opacity:1;transform:none}}

/* responsive */
@media (max-width:900px){
  .nav-links{display:none}
  .lang-switch{margin-left:auto}
  section.stats{grid-template-columns:1fr}
  .stat+.stat{border-left:0;border-top:1px solid var(--line)}
  .reasoning-feature{grid-template-columns:1fr}
  .agent-interpretation{border-left:0;border-top:1px solid #f0e6e2}
  .steps,.ablations{grid-template-columns:1fr}
}
@media (max-width:640px){
  main,.topbar-inner{padding:0 18px}
  .reasoning-section{margin:0 -18px;padding:46px 18px}
  body{font-size:16px}
  br.desktop{display:none}
  .contact-evidence,.agent-interpretation{padding:22px 20px}
  .agent-interpretation blockquote{font-size:19px}
  .scene-context>img{width:120px}
  .stat-value{font-size:26px}
  .abstract p{text-align:left}
  footer{flex-direction:column}
}