:root{--bg:#f5f1e8;--surface:#fffdf8;--surface-2:#f8f4ea;--ink:#233044;--muted:#6b6353;--faint:#9a917d;--line:#ded4c4;--line2:#ece5d8;--accent:#28705a;--accent-soft:#e8f5ef;--teal:#3f8f72;--teal-soft:#e8f5ef;--amber:#b45309;--amber-soft:#f6ecdd;--shadow:0 1px 2px rgba(20,20,30,.04),0 5px 18px rgba(20,20,30,.05)}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);font-family:ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,sans-serif;line-height:1.55;-webkit-font-smoothing:antialiased}
a{color:var(--accent)}
.site{display:flex;align-items:center;justify-content:space-between;padding:14px 22px;border-bottom:1px solid var(--line);background:var(--surface)}
.site .brand{display:flex;align-items:center;gap:9px;font-weight:800;letter-spacing:-.02em;color:var(--ink);text-decoration:none;font-size:1.05rem}
.site .brand img{display:block}
.site .mk{font-size:.85rem;font-weight:700;color:#fff;background:var(--teal);padding:8px 14px;border-radius:9px;text-decoration:none}
.wrap{max-width:1040px;margin:0 auto;padding:28px 22px 60px}
.crumb{font-size:.8rem;color:var(--faint);margin-bottom:16px}
.crumb a{color:var(--muted);text-decoration:none}
.tags{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:10px}
.tag{font-size:.7rem;font-weight:700;text-transform:uppercase;letter-spacing:.03em;padding:4px 10px;border-radius:7px}
.tag.g{background:var(--amber-soft);color:var(--amber)}.tag.s{background:var(--accent-soft);color:var(--accent)}
h1.code{font-family:ui-monospace,"SF Mono",Consolas,monospace;font-size:2.3rem;font-weight:700;letter-spacing:-.02em;margin:2px 0 10px;line-height:1}
.plain{font-size:1.28rem;font-weight:600;line-height:1.34;letter-spacing:-.01em;margin:0 0 7px;max-width:42ch}
.plain-desc{font-size:1rem;color:var(--muted);line-height:1.5;margin:0 0 26px;max-width:64ch}
.rad{position:relative;padding:0 2px 0 1px}
.rad::before{content:"";position:absolute;top:1px;left:-2px;right:0;border-top:1.2px solid currentColor}
/* ---- code-page worksheet sample crops (teaser) ---- */
.ws .band-label{font-size:.7rem;font-weight:800;text-transform:uppercase;letter-spacing:.07em;color:var(--faint);margin:20px 0 12px;display:flex;align-items:center;gap:9px}
.ws .band-label::after{content:"";flex:1;height:1px;background:var(--line)}
.ws .band-label .band-n{color:var(--faint);background:var(--surface-2);border:1px solid var(--line);border-radius:20px;padding:1px 8px;font-size:.66rem}
.wshelf{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-bottom:6px}
.wshelf--single{grid-template-columns:1fr;max-width:560px}
@media(max-width:640px){.wshelf{grid-template-columns:1fr}}
.wcrop{border:1px solid var(--line);border-radius:12px;overflow:hidden;background:var(--surface);display:flex;flex-direction:column;box-shadow:var(--shadow)}
.wcrop-h{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:10px 13px;border-bottom:1px solid var(--line)}
.wcrop-nm{font-size:.9rem;font-weight:600;color:var(--ink)}
.wcrop-tag{font-size:.6rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);background:var(--surface-2);border:1px solid var(--line);border-radius:20px;padding:3px 8px;white-space:nowrap}
.wsclip{position:relative;height:300px;overflow:hidden;background:#fff}
.wsclip--tall{height:380px}
.wsclip-empty{display:flex;align-items:center;justify-content:center;color:var(--faint);font-size:.85rem;height:120px}
.wsframe{position:absolute;top:0;left:0;width:760px;height:1000px;border:0;transform:scale(.5);transform-origin:top left;pointer-events:none}
.wsfade{position:absolute;left:0;right:0;bottom:0;height:80px;background:linear-gradient(rgba(255,255,255,0),#fff);pointer-events:none;z-index:2}
.wcrop-mk{display:block;text-align:center;padding:11px;border-top:1px solid var(--line);font-size:.86rem;font-weight:600;color:var(--teal);text-decoration:none}
.wcrop-mk:hover{background:var(--surface-2)}
/* variant tabs (Design C) */
.wtabs{display:flex;gap:5px;padding:9px 12px;border-bottom:1px solid var(--line);overflow-x:auto;scrollbar-width:none;-webkit-overflow-scrolling:touch}
.wtabs::-webkit-scrollbar{display:none}
.wtab{font:inherit;font-size:.7rem;font-weight:600;white-space:nowrap;color:var(--muted);background:var(--surface);border:1px solid var(--line);border-radius:20px;padding:4px 11px;cursor:pointer;text-decoration:none;flex:none}
.wtab:hover{border-color:var(--accent);color:var(--accent)}
.wtab.on{background:var(--accent-soft);color:var(--accent);border-color:var(--accent)}
.wtab-more{color:var(--faint);align-self:center}
.wview{position:relative;height:300px;overflow:hidden;background:#fff}
.wview--tall{height:380px}
.wpane{position:absolute;inset:0}
.wpane:not(.on){display:none}
.sect{font-size:.72rem;font-weight:800;text-transform:uppercase;letter-spacing:.06em;color:var(--faint);margin:0 0 12px;display:flex;align-items:center;gap:9px}
.sect .cnt{font-weight:700;color:var(--teal);background:var(--teal-soft);border-radius:6px;padding:1px 8px;font-size:.72rem}
section{margin:28px 0}
.wgrid{display:grid;grid-template-columns:1fr 1fr;gap:9px}
@media(max-width:560px){.wgrid{grid-template-columns:1fr}}
.wcard{display:flex;align-items:center;justify-content:space-between;gap:10px;border:1px solid var(--line);border-radius:10px;padding:13px 15px;background:var(--surface);text-decoration:none;color:var(--ink);font-weight:600;font-size:.92rem;box-shadow:var(--shadow)}
.wcard:hover{border-color:color-mix(in srgb,var(--teal) 45%,transparent)}
.wcard .go{font-size:.78rem;font-weight:700;color:var(--teal);white-space:nowrap}
.ws.gap .gapnote{color:var(--muted);font-size:.92rem;margin:0 0 12px}
.official{background:var(--surface);border:1px solid var(--line);border-left:3px solid var(--amber);border-radius:11px;padding:14px 16px;box-shadow:var(--shadow)}
.ol{font-size:.68rem;font-weight:800;text-transform:uppercase;letter-spacing:.06em;margin-bottom:8px}
.official .ol{color:var(--amber)}
.parts .ol{color:var(--accent)}
.official p{font-family:Georgia,"Times New Roman",serif;font-size:1rem;line-height:1.55;margin:0;color:var(--ink)}
.parts{border:1px solid var(--line);border-radius:11px;background:var(--surface);padding:14px 16px;box-shadow:var(--shadow)}
.parts .part{display:grid;grid-template-columns:auto 1fr;gap:12px;align-items:start;padding:10px 0;border-top:1px solid var(--line2)}
.parts .part:first-of-type{border-top:0;padding-top:2px}
.parts .plet{width:25px;height:25px;border-radius:7px;background:var(--accent-soft);color:var(--accent);display:grid;place-items:center;font-weight:800;font-family:ui-monospace,Consolas,monospace;font-size:.82rem}
.parts .ptext{font-size:.86rem;color:var(--ink);line-height:1.45}
.parts .sub{display:block;margin-top:3px;font-family:ui-monospace,Consolas,monospace;font-size:.68rem;color:var(--faint)}
/* reference block: wide main column (official + parts) + progression rail (builds-on / leads-to) */
.refblock{display:grid;grid-template-columns:minmax(0,1.9fr) minmax(0,1fr);gap:16px;align-items:start}
.rb-main,.rb-rail{display:flex;flex-direction:column;gap:14px;min-width:0}
.rb-rail .lane{border:1px solid var(--line);border-radius:11px;background:var(--surface);padding:14px 16px;box-shadow:var(--shadow)}
@media(max-width:720px){.refblock{grid-template-columns:1fr}}
.lane-l{font-size:.72rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--muted);margin-bottom:9px}
.chips{display:flex;flex-direction:column;gap:7px}
.chip{display:flex;align-items:baseline;gap:9px;border:1px solid var(--line);border-radius:9px;padding:8px 11px;background:var(--surface-2);text-decoration:none}
.chip:hover{border-color:var(--accent)}
.chip .c{font-family:ui-monospace,Consolas,monospace;font-size:.78rem;font-weight:700;color:var(--accent);white-space:nowrap}
.chip .nm{font-size:.85rem;color:var(--muted)}
.chip.dead{opacity:.6}
.foot{max-width:1040px;margin:0 auto;padding:22px;border-top:1px solid var(--line);color:var(--muted);font-size:.9rem}
.foot a{color:var(--accent);text-decoration:none}
/* ---- index (/ccss/) : standards browser ---- */
.wrap.idx-page{max-width:1040px}
.idx-page .pagehead{display:flex;justify-content:space-between;align-items:flex-end;gap:24px;margin:0 0 22px}
.idx-page .lead{flex:1;min-width:0}
.idx-page .pagehead h1{font-family:'Short Stack',cursive;font-weight:400;font-size:clamp(1.85rem,3.6vw,2.3rem);letter-spacing:0;line-height:1.12;margin:0 0 10px}
.idx-page .sub{font-size:1.04rem;color:var(--muted);line-height:1.5;margin:0}
.idx-page .stat{flex:none;text-align:right;border-left:1px solid var(--line);padding-left:20px}
.idx-page .stat b{display:block;font-size:1.7rem;font-weight:800;letter-spacing:-.02em;line-height:1;font-variant-numeric:tabular-nums}
.idx-page .stat span{font-size:.76rem;color:var(--faint);text-transform:uppercase;letter-spacing:.05em;font-weight:700}
@media(max-width:620px){.idx-page .pagehead{display:block}.idx-page .stat{display:none}}
.browser{display:grid;grid-template-columns:212px 1fr;gap:34px;align-items:start;border-top:1px solid var(--line)}
.sidebar{align-self:start;padding:22px 0}
.side-h{font-size:.66rem;font-weight:800;text-transform:uppercase;letter-spacing:.08em;color:var(--faint);height:30px;display:flex;align-items:center;padding:0 11px;margin:0 0 4px}
.sidebar a{display:flex;align-items:center;justify-content:space-between;gap:8px;font-size:.855rem;color:var(--muted);text-decoration:none;border-radius:8px;padding:7px 11px;line-height:1.3}
.sidebar a:hover{background:var(--surface);color:var(--ink)}
.sidebar a.active{background:var(--accent-soft);color:var(--accent);font-weight:700}
.sidebar a .n{font-size:.7rem;font-weight:700;color:var(--faint);font-variant-numeric:tabular-nums;flex:none}
.sidebar a.off{opacity:.32;pointer-events:none}
.main{min-width:0}
.toolbar{display:flex;align-items:center;gap:12px;flex-wrap:wrap;background:var(--bg);padding:22px 0 13px;border-bottom:1px solid var(--line)}
.tb-l{font-size:.68rem;font-weight:800;text-transform:uppercase;letter-spacing:.07em;color:var(--faint)}
.gradebar{display:flex;flex-wrap:wrap;gap:6px}
.gb{font:inherit;font-size:.8rem;font-weight:600;color:var(--muted);background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:5px 11px;cursor:pointer}
.gb:hover{border-color:var(--accent);color:var(--accent)}
.gb.on{background:var(--accent-soft);color:var(--accent);border-color:var(--accent);font-weight:700}
.count{margin-left:auto;font-size:.78rem;color:var(--faint);white-space:nowrap;font-variant-numeric:tabular-nums}
.csec{margin:26px 0 0;scroll-margin-top:12px}
.csec:first-of-type{margin-top:22px}
.csec h2{font-size:1.06rem;letter-spacing:-.01em;margin:0 0 13px;display:flex;align-items:baseline;gap:10px;flex-wrap:wrap}
.csec .cc{font-size:.74rem;font-weight:600;color:var(--faint)}
.idxgrid{display:grid;grid-template-columns:1fr 1fr;gap:9px}
@media(max-width:560px){.idxgrid{grid-template-columns:1fr}}
.idx{display:flex;flex-direction:column;gap:6px;border:1px solid var(--line);border-radius:10px;padding:11px 13px;background:var(--surface);text-decoration:none;box-shadow:var(--shadow)}
.idx .idxtop{display:flex;align-items:center;gap:8px;width:100%}
.idx:hover{border-color:color-mix(in srgb,var(--accent) 45%,transparent)}
.idx .gr{font-family:ui-monospace,Consolas,monospace;font-size:.6rem;font-weight:800;color:var(--muted);background:var(--surface-2);border:1px solid var(--line);border-radius:5px;padding:2px 5px;min-width:23px;text-align:center;flex:none;margin-top:1px}
.idx .tags{display:flex;gap:4px;flex-wrap:wrap;margin-left:auto;flex:none}
.idx .ctag{background:var(--surface-2);border:1px solid var(--line);border-radius:20px;padding:1px 8px;font-size:.62rem;font-weight:700;color:var(--muted);white-space:nowrap}
.idx .c{font-family:ui-monospace,Consolas,monospace;font-size:.76rem;font-weight:700;color:var(--accent);white-space:nowrap;flex:none;margin-top:1px}
.idx .nm{font-size:.85rem;color:var(--ink);line-height:1.32;display:-webkit-box;-webkit-line-clamp:2;-webkit-box-orient:vertical;overflow:hidden;width:100%}
.idx.gap{opacity:.66}.idx.gap .c{color:var(--muted)}
@media(min-width:721px){
  html,body.idx-body{height:100%}
  body.idx-body{overflow:hidden;display:flex;flex-direction:column}
  .idx-body .site{flex:none}
  .idx-body .wrap.idx-page{flex:1;min-height:0;display:flex;flex-direction:column;overflow:hidden;padding-bottom:14px}
  .idx-body .crumb,.idx-body .pagehead{flex:none}
  .idx-body .browser{flex:1;min-height:0;overflow:hidden;align-items:stretch}
  .idx-body .sidebar{overflow-y:auto;align-self:stretch}
  .idx-body .main{display:flex;flex-direction:column;min-height:0;overflow:hidden}
  .idx-body .toolbar{flex:none}
  .idx-body #sections{flex:1;min-height:0;overflow-y:auto;padding-bottom:24px}
  .idx-body .foot{flex:none}
}
@media(max-width:720px){
  .browser{grid-template-columns:1fr;gap:0;border-top:none}
  .sidebar{padding:0 0 4px;display:flex;flex-direction:row;overflow-x:auto;gap:6px;margin:0 0 4px}
  .side-h{display:none}
  .sidebar a{border:1px solid var(--line);border-radius:20px;white-space:nowrap;padding:6px 12px}
  .sidebar a .n{display:none}
  .toolbar{position:sticky;top:0;z-index:5;border-top:1px solid var(--line);padding-top:14px}
  .csec{scroll-margin-top:64px}
}
/* ---- code-page mobile ---- */
@media(max-width:560px){
  .wrap{padding:22px 16px 46px}
  .site{padding:12px 15px}
  .site .brand{font-size:1rem}
  .site .mk{font-size:.8rem;padding:7px 12px}
  h1.code{font-size:1.95rem}
  .plain-desc{font-size:.96rem;margin-bottom:20px}
  .official{padding:14px 15px}
  .wshelf{gap:13px}
}