:root{
  --paper:#F4F5F2;--surface:#FFF;--ink:#1B1F1C;--ink-2:#454B46;--muted:#787F79;
  --line:#DCE0D8;--line-2:#C6CCC2;--accent:#0F5C52;--accent-soft:#E4EDE9;
  --warn:#A2442A;--warn-soft:#F5E7E2;
  --d1:#0F5C52;--d2:#2E6F9E;--d3:#A87029;--d4:#75497A;--d5:#5C7A3A;
  --shadow:0 1px 2px rgba(27,31,28,.05);
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --paper:#131612;--surface:#1B1F1A;--ink:#E9ECE4;--ink-2:#B9BFB6;--muted:#868D84;
  --line:#2C312A;--line-2:#3B4239;--accent:#5DB3A0;--accent-soft:#1E2C28;
  --warn:#D4785C;--warn-soft:#2C1F1A;
  --d1:#5DB3A0;--d2:#6FA6D2;--d3:#D2A057;--d4:#B084B4;--d5:#93B364;--shadow:none;
}}
:root[data-theme="dark"]{
  --paper:#131612;--surface:#1B1F1A;--ink:#E9ECE4;--ink-2:#B9BFB6;--muted:#868D84;
  --line:#2C312A;--line-2:#3B4239;--accent:#5DB3A0;--accent-soft:#1E2C28;
  --warn:#D4785C;--warn-soft:#2C1F1A;
  --d1:#5DB3A0;--d2:#6FA6D2;--d3:#D2A057;--d4:#B084B4;--d5:#93B364;--shadow:none;
}
*{box-sizing:border-box}
body{margin:0;background:var(--paper);color:var(--ink);font-size:16px;line-height:1.75;
  font-family:"IBM Plex Sans",-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;
  -webkit-font-smoothing:antialiased}
.mono{font-family:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,monospace}
.site-shell{max-width:700px;margin:0 auto;padding:52px 24px 96px}
.hidden{display:none!important}
h1{font-size:clamp(28px,5.4vw,40px);line-height:1.25;margin:14px 0 20px;font-weight:600;letter-spacing:-.02em;text-wrap:balance}
h2{font-size:20px;font-weight:600;margin:34px 0 10px}
p{margin:0 0 14px;color:var(--ink-2);max-width:62ch}
strong{color:var(--ink);font-weight:600}
.section-label{font-family:"IBM Plex Mono",monospace;font-size:11px;letter-spacing:.16em;
  text-transform:uppercase;color:var(--muted);margin:0 0 6px}
ul{margin:0 0 14px;padding-left:20px;color:var(--ink-2)}
li{margin-bottom:6px}
.disc{border:1px solid var(--line-2);background:var(--surface);padding:16px 18px;margin:24px 0;
  font-size:14px;line-height:1.7;color:var(--ink-2);box-shadow:var(--shadow)}
.disc p{margin:0 0 9px;font-size:14px}
.disc p:last-child{margin:0}
.unlock-card{border-top:2px solid var(--ink);padding-top:26px;margin-top:34px}
.unlock-row{display:flex;gap:10px;flex-wrap:wrap;margin:18px 0 10px}
input[type=text],input[type=password]{flex:1;min-width:230px;padding:12px 14px;font-size:15px;
  font-family:"IBM Plex Mono",monospace;letter-spacing:.06em;background:var(--surface);
  color:var(--ink);border:1px solid var(--line-2);border-radius:2px}
input:focus{outline:2px solid var(--accent);outline-offset:1px}
button{font-family:inherit;font-size:15px;cursor:pointer;background:var(--accent);color:var(--paper);
  border:none;padding:12px 28px;border-radius:2px;font-weight:500;transition:opacity .15s}
button:hover:not(:disabled){opacity:.86}
button:disabled{opacity:.45;cursor:default}
button.ghost{background:none;color:var(--muted);padding:12px 0}
button.ghost:hover:not(:disabled){color:var(--ink)}
.status{font-size:13.5px;color:var(--warn);min-height:20px;margin:6px 0 0}
.progress{position:fixed;top:0;left:0;height:2px;background:var(--accent);width:0;z-index:50;transition:width .25s}
.test-head{display:flex;justify-content:space-between;align-items:baseline;
  font-family:"IBM Plex Mono",monospace;font-size:12px;color:var(--muted);letter-spacing:.08em;
  padding-bottom:10px;border-bottom:1px solid var(--line);margin-bottom:22px}
fieldset{border:none;padding:0;margin:0}
legend{font-size:20px;line-height:1.6;font-weight:500;margin-bottom:16px;text-wrap:balance;color:var(--ink)}
.qnote{font-size:13.5px;color:var(--muted);line-height:1.65;margin:0 0 18px;
  padding-left:13px;border-left:2px solid var(--line-2);max-width:58ch}
.option{display:grid;grid-template-columns:22px 1fr;gap:11px;align-items:start;
  padding:14px 13px;border-bottom:1px solid var(--line);border-left:3px solid transparent;
  cursor:pointer;color:var(--ink-2);font-size:15.5px;line-height:1.62;transition:background .12s,border-color .12s,color .12s}
.option:first-of-type{border-top:1px solid var(--line)}
.option:hover{background:var(--surface);border-left-color:var(--line-2);color:var(--ink)}
.option input{margin:5px 0 0;accent-color:var(--accent)}
.option:has(input:checked){background:var(--accent-soft);border-left-color:var(--accent);color:var(--ink);font-weight:500}
.test-nav{display:flex;justify-content:space-between;align-items:center;margin-top:24px;gap:12px}
.sub{font-size:17px;color:var(--ink-2);margin:0 0 26px}
.unlock-card{border-top:2px solid var(--ink);border-bottom:1px solid var(--line);
  padding:22px 0 20px;margin:0 0 8px}
.unlock-row{margin:0 0 8px}
.hint{font-size:13.5px;color:var(--muted);margin:10px 0 0;line-height:1.65}
details.fold{border-bottom:1px solid var(--line)}
details.fold>summary{list-style:none;cursor:pointer;padding:15px 0;font-size:14.5px;
  font-weight:500;color:var(--ink-2);display:flex;align-items:center;gap:10px}
details.fold>summary::-webkit-details-marker{display:none}
details.fold>summary::before{content:"+";font-family:"IBM Plex Mono",monospace;font-size:15px;color:var(--muted);width:12px}
details.fold[open]>summary::before{content:"−"}
details.fold>summary:hover{color:var(--ink)}
details.fold>summary:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
#landingCopy{padding:34px 0 0}
#landingCopy h2{font-size:16px;margin:22px 0 8px}
#landingCopy h2:first-child{margin-top:4px}
#landingCopy p,#landingCopy li{font-size:15px}