/* 复用主站的墨蓝、纸白、字体栈与 24px 圆角。实验内不加载城市动效或统计脚本。 */
:root{
  --ink:#243048;--muted:#56657b;--paper:#f8f9fc;--bg:#e9ecf2;--panel:#fff;--line:#53688426;
  --accent:#455770;--accent-ink:#fff;--chip:#e9edf5;--focus:#536f99;--radius:24px;--radius-inner:6px;
  --warn-bg:#fbf3e4;--warn-ink:#795a22;--ok:#3d6b5a;--bad:#a13e42;--shadow:0 12px 35px #23334d0b;
  --sans:'MoYu Interface Grotesk','MoYu Interface Latin','MoYu Interface Han','PingFang SC',sans-serif;
  --serif:'MoYu Numerals','MoYu Literary Latin','MoYu Literary Han','Songti SC',serif;
  color-scheme:light;
}
:root[data-theme=dark]{--ink:#e3e8f1;--muted:#b2bfd1;--paper:#202c3d;--bg:#101a2b;--panel:#26334a;--line:#b7c8e52b;--accent:#b6c9e4;--accent-ink:#1a2940;--chip:#34435d;--focus:#bfd3ed;--warn-bg:#403424;--warn-ink:#ebd3a8;--ok:#9ccab3;--bad:#f1a7ab;--shadow:0 12px 35px #050d1c24;color-scheme:dark}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:15px/1.8 var(--sans);min-height:100vh;display:flex;flex-direction:column}
body::before{content:'';position:fixed;inset:0;z-index:-1;pointer-events:none;background:radial-gradient(ellipse at 10% 0%,#cfdae8,transparent 55%),radial-gradient(ellipse at 95% 90%,#c8ccda,transparent 55%)}
body.home::before{background:linear-gradient(#edf1f8c9,#edf1f8e8),url('/site-assets/twilight-scene.webp') center/cover no-repeat}
[data-theme=dark] body::before{background:radial-gradient(ellipse at 10% 0%,#283956,transparent 60%)}
[data-theme=dark] body.home::before{background:linear-gradient(#0f1a2fc9,#0f1a2fe8),url('/site-assets/twilight-scene.webp') center/cover no-repeat}
button,input,textarea,select{font:inherit;color:inherit;touch-action:manipulation}
a{color:inherit;text-decoration:none;touch-action:manipulation}
button{cursor:pointer;font-weight:400}button:disabled{cursor:not-allowed}
h1,h2,h3,p{margin:0}h1,h2,h3,strong,b{font-weight:400}
:focus-visible{outline:2px solid var(--focus);outline-offset:4px}
h1[tabindex="-1"]:focus{outline:none}
[hidden]{display:none!important}
.skip{position:fixed;top:-80px;left:12px;z-index:30;padding:10px 18px;background:var(--panel);border-radius:var(--radius)}.skip:focus{top:10px}
.lab-header{display:flex;align-items:center;gap:20px;width:100%;max-width:1280px;min-height:96px;margin:0 auto;padding:20px 40px}
.lab-brand{display:inline-flex;flex-shrink:0}.lab-brand img{display:block;width:152px;height:auto;object-fit:contain;filter:brightness(0);opacity:.82}
[data-theme=dark] .lab-brand img{filter:brightness(0) invert(1);opacity:.94}
.lab-section{font-size:15px;border-left:1px solid var(--line);padding-left:20px;white-space:nowrap}.lab-section small{font-size:10px;color:var(--muted);letter-spacing:1px;margin-left:8px}
.lab-header .spacer{flex:1}.header-link{font-size:12px;white-space:nowrap;color:var(--muted)}.header-link:hover{color:var(--ink)}
.theme-toggle{border:1px solid var(--line);background:transparent;border-radius:50%;width:38px;height:38px;flex-shrink:0;font:22px/1 var(--sans)}
.lang-toggle{border:1px solid var(--line);background:transparent;border-radius:var(--radius);height:38px;min-width:50px;padding:0 13px;flex-shrink:0;font:500 11px/1 var(--sans);letter-spacing:.08em;color:var(--muted);transition:color .15s,border-color .15s}
.lang-toggle:hover{color:var(--ink);border-color:var(--accent)}
.in-study .theme-toggle,.in-study .lang-toggle{display:none}
.lab-main{width:100%;max-width:800px;margin:0 auto;padding:8px 24px 48px;flex:1}
.lab-footer{width:calc(100% - 80px);max-width:1200px;margin:0 auto;padding:25px 0 30px;border-top:1px solid var(--line);color:var(--muted);font-size:12px}
.footer-main{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}.footer-main nav{display:flex;gap:20px}.lab-footer a:hover{text-decoration:underline;text-underline-offset:4px}
.footer-note{font-size:11px;margin-top:9px}.footer-registration{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:12px;font-size:11px;margin-top:18px}.footer-registration a{display:inline-flex;align-items:center;gap:5px}.footer-registration img{display:inline-block;width:16px;height:16px;object-fit:contain}
.test-banner{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:12px;width:100%;padding:7px 20px;background:var(--warn-bg);color:var(--warn-ink);font-size:12px;margin-bottom:16px;border-block:1px solid #a7813d1a}
.test-banner select{width:auto;max-width:230px;min-height:30px;padding:3px 12px;font-size:12px}.test-banner a{font-size:12px;text-decoration:underline;text-underline-offset:3px}
.lang-notice{display:flex;align-items:center;justify-content:center;flex-wrap:wrap;gap:9px 16px;width:100%;padding:9px 20px;background:var(--panel);color:var(--ink);font-size:12.5px;margin-bottom:16px;border-block:1px solid var(--line)}
.lang-notice p{display:flex;flex-wrap:wrap;align-items:baseline;justify-content:center;gap:8px}
.lang-notice small{color:var(--muted);font-size:11px;letter-spacing:.02em}
.lang-notice-actions{display:flex;align-items:center;gap:8px}
.lang-notice button{min-height:30px;padding:4px 14px;border-radius:999px;border:1px solid var(--line);background:transparent;color:var(--muted);font-size:12px;line-height:1.2;transition:color .15s,border-color .15s,background .15s,opacity .15s}
.lang-notice button:hover{color:var(--ink);border-color:var(--accent)}
.lang-notice .lang-notice-switch{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
.lang-notice .lang-notice-switch:hover{color:var(--accent-ink);opacity:.88}
.card{background:var(--panel);border:1px solid var(--line);border-radius:var(--radius);padding:32px 36px;box-shadow:var(--shadow)}.card+.card{margin-top:16px}
.title{font-family:var(--serif);font-size:27px;line-height:1.5;letter-spacing:.6px;margin-bottom:18px}.subtitle{font-size:12px;color:var(--muted);margin-bottom:7px;letter-spacing:.5px}
.prose p{margin:0 0 13px;line-height:1.95}.prose p:last-child{margin-bottom:0}.muted{color:var(--muted)}.small{font-size:13px}
.meta{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px}.chip{display:inline-block;font-size:11px;padding:3px 11px;border-radius:var(--radius);background:var(--chip);color:var(--muted)}
.actions{display:flex;justify-content:flex-end;flex-wrap:wrap;align-items:center;gap:12px;margin-top:28px;padding-top:22px;border-top:1px solid var(--line)}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:44px;min-width:136px;padding:10px 24px;border-radius:var(--radius);border:1px solid transparent;background:var(--accent);color:var(--accent-ink);font-size:14px;text-align:center;line-height:1.5;transition:opacity .15s,background .15s}
.btn:hover{opacity:.88}.btn:disabled{opacity:.42}.btn.secondary{background:transparent;color:var(--ink);border-color:var(--line)}.btn.ghost{background:transparent;color:var(--muted);border:0;min-width:0;min-height:36px;padding:5px 10px;font-size:12px}.btn.danger{background:var(--bad);color:#fff}.btn.small{min-width:0;min-height:34px;padding:6px 15px;font-size:12px}
.survey-stages{display:flex;justify-content:space-between;list-style:none;margin:7px 8px 24px;padding:0;gap:8px}.survey-stages li{display:flex;align-items:center;gap:8px;color:var(--muted);font-size:12px;white-space:nowrap}.stage-number{display:grid;place-items:center;width:25px;height:25px;border:1px solid var(--line);border-radius:50%;font-size:11px;background:var(--paper)}.survey-stages .current{color:var(--ink)}.current .stage-number{background:var(--accent);color:var(--accent-ink);border-color:var(--accent)}.done .stage-number{color:var(--accent);background:var(--chip)}
.survey-heading{display:flex;align-items:center;gap:20px;justify-content:space-between}.survey-heading .title{font:22px/1.55 var(--serif);margin-bottom:0}.survey-count{font-size:14px;color:var(--muted);font-variant-numeric:tabular-nums;white-space:nowrap}
.progress{display:flex;gap:12px;align-items:center;margin:18px 0 26px;font-size:11px;color:var(--muted);white-space:nowrap}.progress progress{appearance:none;flex:1;width:0;height:5px;border:0;background:var(--chip);border-radius:8px;overflow:hidden}.progress progress::-webkit-progress-bar{background:var(--chip);border-radius:8px}.progress progress::-webkit-progress-value{background:var(--accent);border-radius:8px}.progress progress::-moz-progress-bar{background:var(--accent);border-radius:8px}
.question-heading{display:flex;gap:12px;align-items:center;border-top:1px solid var(--line);padding-top:25px;margin-bottom:24px}.question-number{font-size:21px;line-height:1;color:var(--accent);font-variant-numeric:tabular-nums;align-self:flex-start;padding-top:3px}.question-heading h2{font-size:15px}.question-hint{font-size:12px;color:var(--muted);margin-top:3px}.question{font-size:18px;line-height:1.8;margin-bottom:20px}.question-body .title{font:18px/1.65 var(--sans)}
.options{display:grid;gap:10px}.option{display:flex;align-items:center;gap:12px;padding:13px 17px;min-height:52px;border:1px solid var(--line);border-radius:var(--radius);cursor:pointer;background:var(--panel);font-size:15px;transition:background .15s,border-color .15s}.option:hover{background:var(--paper)}.option input{margin:0;width:18px;height:18px;accent-color:var(--accent);flex-shrink:0}.option:has(input:checked){background:var(--chip);border-color:var(--accent)}.option:has(input:disabled){cursor:default}
.confidence{margin-top:24px;padding-top:18px;border-top:1px dashed var(--line)}.confidence label{display:block;font-size:13px;margin-bottom:12px}.confidence output{font-size:15px;color:var(--accent);font-variant-numeric:tabular-nums}.confidence input[type=range]{width:100%;accent-color:var(--accent);height:24px;margin:0;cursor:pointer}.confidence .ends{display:flex;justify-content:space-between;color:var(--muted);font-size:11px;margin-top:4px}
.checks{display:grid;gap:10px;margin-top:22px}.check{display:flex;align-items:flex-start;gap:12px;padding:13px 16px;border:1px solid var(--line);border-radius:var(--radius);cursor:pointer;background:var(--paper);font-size:14px}.check input{margin:5px 0 0;width:18px;height:18px;flex-shrink:0;accent-color:var(--accent)}.check:has(input:checked){background:var(--chip);border-color:var(--accent)}
.yesno{display:grid;gap:24px;margin-top:24px;counter-reset:eligibility}.yesno fieldset{border:0;margin:0;padding:0;min-width:0;counter-increment:eligibility}.yesno legend{font-size:15px;padding:0 0 12px}.yesno legend::before{content:counter(eligibility) '. ';color:var(--muted)}.yesno .row{display:flex;gap:10px}.yesno .option{flex:1;max-width:170px}
.stimulus,.material{border:1px solid var(--line);border-radius:var(--radius);padding:20px;background:var(--paper);margin-bottom:18px}.material{font:16px/2 var(--sans)}.material h3{font-size:17px;margin-bottom:10px}.material p+p{margin-top:12px}
.locked{font-size:13px;padding:11px 16px;border-radius:var(--radius);background:var(--chip);margin-bottom:20px;color:var(--muted)}.advice{border:1px solid var(--line);border-left:3px solid var(--accent);border-radius:var(--radius);background:var(--paper);padding:17px 20px;margin-bottom:23px}.advice .who{font-size:12px;color:var(--muted);margin-bottom:6px}.advice .answer{font-size:17px}.advice .why{font-size:14px;line-height:1.9;color:var(--muted);margin-top:8px}
.thinking{display:flex;align-items:center;gap:10px;padding:18px 0;color:var(--muted);font-size:13px}.dots{display:flex;gap:4px}.dots i{width:5px;height:5px;border-radius:50%;background:currentColor;animation:blink 1s infinite}.dots i:nth-child(2){animation-delay:.2s}.dots i:nth-child(3){animation-delay:.4s}@keyframes blink{0%,100%{opacity:.2}50%{opacity:1}}
.claim{margin-bottom:20px}.claim .source{font-size:11px;color:var(--muted);margin-bottom:10px}.claim h3{font-size:19px;line-height:1.8}.claim p{font-size:14px;margin-top:10px;color:var(--muted)}
.section-label{font-size:13px;color:var(--muted);margin:22px 0 12px}.evidence{display:grid;gap:8px;margin-bottom:20px}.evidence-item{border:1px solid var(--line);border-radius:var(--radius);background:var(--paper);overflow:hidden}.evidence-item>button{display:flex;justify-content:space-between;align-items:center;gap:12px;width:100%;text-align:left;padding:12px 17px;border:0;background:transparent;font-size:13px;min-height:46px}.evidence-item>button::after{content:'展开 +';font-size:11px;color:var(--muted);white-space:nowrap}.evidence-item.open>button::after{content:'收起 −'}.evidence-item .content{padding:0 17px 16px;font-size:13px;color:var(--muted);line-height:1.9}
.coverage-notice,.nudge,.uncertainty-warning{border-radius:var(--radius);padding:12px 16px;font-size:13px;line-height:1.85;margin-bottom:20px}.coverage-notice{border:1px solid var(--line);background:var(--chip)}.nudge,.uncertainty-warning{background:var(--warn-bg);color:var(--warn-ink)}
textarea{display:block;width:100%;min-height:190px;padding:16px 18px;resize:vertical;border:1px solid var(--line);border-radius:var(--radius);background:var(--paper);font:15px/1.9 var(--sans)}.counter{font-size:11px;color:var(--muted);text-align:right;margin-top:7px;font-variant-numeric:tabular-nums}.counter.bad{color:var(--bad)}
.items{display:grid;gap:30px;counter-reset:items}.item{border:0;border-bottom:1px solid var(--line);padding:0 0 26px;margin:0;min-width:0}.item:last-child{border:0;padding-bottom:0}.item legend{font-size:15px;padding:0 0 16px;line-height:1.9;width:100%}.required-label{font-size:10px;color:var(--muted);margin-left:10px;white-space:nowrap}.likert{display:grid;grid-auto-flow:column;grid-auto-columns:1fr;gap:7px}.likert label{position:relative;display:grid;place-items:center;border:1px solid var(--line);border-radius:var(--radius);min-height:46px;cursor:pointer;background:var(--paper);font-size:14px}.likert input{position:absolute;opacity:0;width:100%;height:100%;margin:0;cursor:pointer}.likert label:has(input:checked){background:var(--accent);color:var(--accent-ink);border-color:var(--accent)}.likert label:has(input:focus-visible){outline:2px solid var(--focus);outline-offset:3px}.likert-ends{display:flex;justify-content:space-between;font-size:11px;color:var(--muted);margin-top:8px;gap:20px}
.code{display:inline-block;padding:10px 18px;border-radius:var(--radius);background:var(--chip);font:20px/1.5 var(--sans);letter-spacing:2px;margin:8px 0}.notice{padding:13px 17px;border-radius:var(--radius);background:var(--chip);color:var(--muted);font-size:13px;margin-top:18px}.error{color:var(--bad);font-size:13px;margin-top:12px}.row{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
details{font-size:13px}summary{cursor:pointer}
select{padding:10px 14px;min-height:42px;width:100%;border-radius:var(--radius);border:1px solid var(--line);background:var(--paper)}
dialog{border:1px solid var(--line);border-radius:var(--radius);padding:28px;background:var(--panel);color:var(--ink);width:460px;max-width:calc(100% - 32px);box-shadow:var(--shadow)}dialog::backdrop{background:#0f18267a;backdrop-filter:blur(4px)}dialog h2{font-size:20px;margin-bottom:12px}dialog .check{margin-top:16px}dialog select{margin:8px 0}
.offline{position:fixed;bottom:20px;left:50%;transform:translateX(-50%);border-radius:var(--radius);background:var(--ink);color:var(--paper);padding:11px 20px;font-size:13px;max-width:calc(100% - 32px);z-index:20;box-shadow:var(--shadow)}
@media(max-width:900px){.lab-header{padding:18px 24px;gap:15px;min-height:80px}.lab-brand img{width:125px}.lab-section{font-size:13px;padding-left:15px}.lab-section small{display:none}.lab-footer{width:calc(100% - 48px)}}
@media(max-width:600px){body{font-size:14px}.lab-header{padding:16px;min-height:72px;gap:12px}.lab-brand img{width:108px}.lab-section{padding-left:12px;font-size:12px}.header-link{display:none}.lab-header:has(#withdraw-open:not([hidden])) .header-link{display:none}.theme-toggle{width:32px;height:32px;font-size:20px}.lang-toggle{height:32px;min-width:44px;padding:0 10px;font-size:10px}.lab-main{padding:0 12px 28px}.card{padding:23px 20px}.title{font-size:24px}.survey-heading{align-items:start;gap:12px}.survey-heading .title{font-size:20px}.survey-count{font-size:12px;padding-top:6px}.survey-stages{margin:4px 4px 20px;gap:6px}.survey-stages li{font-size:10px;gap:5px}.stage-number{width:21px;height:21px;font-size:10px}.test-banner{font-size:11px;gap:8px;padding:8px 12px}.test-banner select{max-width:190px;font-size:11px}.question-heading{padding-top:20px;margin-bottom:20px}.question-heading h2{font-size:14px}.question-hint{font-size:11px}.question,.claim h3{font-size:17px}.option{min-height:50px;padding:12px 15px;font-size:14px}.actions{gap:10px;margin-top:24px;padding-top:20px}.actions .btn{flex:1;min-width:0;font-size:13px}.confidence{margin-top:22px}.material{padding:17px;font-size:15px}.likert{gap:5px}.likert label{min-height:43px;font-size:13px}.lab-footer{width:calc(100% - 32px);padding:22px 0;font-size:11px}.footer-main{justify-content:center;text-align:center;gap:9px}.footer-main nav{gap:18px}.footer-note{text-align:center;font-size:10px}.footer-registration{flex-direction:column;gap:6px;font-size:10px;margin-top:16px}.footer-registration>span{display:none}.yesno .option{max-width:none}dialog{padding:24px 20px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*::before,*::after{animation:none!important;transition:none!important}}
/* 英文界面：收紧字距、补译伪元素文案，避免拉丁字母在中文版式里显得松散。 */
html[lang=en] .home h1,html[lang=en] .title,html[lang=en] .home h2{letter-spacing:0}
html[lang=en] .hero-description{line-height:1.9}
html[lang=en] .map-node{font-size:10px;padding:6px 9px;gap:6px}
/* 英文节点文字比中文长，缩小中心标题并让四个节点离圆心更远，避免压住 Human × AI。 */
html[lang=en] .map-center>span{font-size:24px;letter-spacing:.02em;white-space:nowrap}
html[lang=en] .map-center small{font-size:9px;letter-spacing:1.2px}
html[lang=en] .node-0{top:-8px;left:-28px}
html[lang=en] .node-1{top:62px;right:-54px}
html[lang=en] .node-2{bottom:-8px;right:-28px}
html[lang=en] .node-3{bottom:62px;left:-54px}
@media(max-width:900px){
  html[lang=en] .map-center>span{font-size:21px}
  html[lang=en] .map-node{font-size:9px;padding:5px 8px}
  html[lang=en] .node-0{top:-6px;left:-22px}
  html[lang=en] .node-1{top:56px;right:-52px}
  html[lang=en] .node-2{bottom:-6px;right:-26px}
  html[lang=en] .node-3{bottom:56px;left:-52px}
}
@media(max-width:650px){
  html[lang=en] .map-center>span{font-size:17px}
  html[lang=en] .map-node{font-size:8.5px;padding:4px 7px;gap:5px}
  html[lang=en] .map-node small{font-size:8px}
  html[lang=en] .node-0{top:-6px;left:-14px}
  html[lang=en] .node-1{top:44px;right:-38px}
  html[lang=en] .node-2{bottom:-6px;right:-14px}
  html[lang=en] .node-3{bottom:44px;left:-38px}
}
html[lang=en] .evidence-item>button::after{content:'Open +'}
html[lang=en] .evidence-item.open>button::after{content:'Close −'}
html[lang=en] .lab-section small{letter-spacing:.5px}