:root{
  --bg:#fbfbf8;--surface:#fff;--code-bg:#f4f4ef;--ink:#15171c;--muted:#5b616e;--line:#e2e2da;
  --accent:#2442d6;--accent-soft:#e8ecff;--mark:#fff1c2;
  --tk-c:#6b7280;--tk-s:#0f7a4f;--tk-k:#a11ea8;--tk-n:#b4490a;--tk-f:#2442d6;--tk-p:#0b6a8a;--tk-t:#b4232f;
  --sans:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei","Noto Sans SC",sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono",monospace;
  color-scheme:light;
}
@media (prefers-color-scheme:dark){
  :root:not([data-theme=light]){
    --bg:#101216;--surface:#171a20;--code-bg:#171a20;--ink:#e9eaee;--muted:#9aa1ad;--line:#2a2e37;
    --accent:#93a6ff;--accent-soft:#1e2444;--mark:#4a3d12;
    --tk-c:#8a919e;--tk-s:#6fd3a4;--tk-k:#e39bf0;--tk-n:#f2ac72;--tk-f:#93a6ff;--tk-p:#6fc5e3;--tk-t:#f28b92;
    color-scheme:dark;
  }
}
:root[data-theme=dark]{
  --bg:#101216;--surface:#171a20;--code-bg:#171a20;--ink:#e9eaee;--muted:#9aa1ad;--line:#2a2e37;
  --accent:#93a6ff;--accent-soft:#1e2444;--mark:#4a3d12;
  --tk-c:#8a919e;--tk-s:#6fd3a4;--tk-k:#e39bf0;--tk-n:#f2ac72;--tk-f:#93a6ff;--tk-p:#6fc5e3;--tk-t:#f28b92;
  color-scheme:dark;
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%;scroll-padding-top:24px}
body{margin:0;background:var(--bg);color:var(--ink);font:17px/1.85 var(--sans);display:flex;flex-direction:column;min-height:100vh}
main{flex:1}
a{color:var(--accent);text-underline-offset:3px}
h1,h2,h3,p,ol,ul,figure{margin:0}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
[hidden]{display:none!important}
.wrap{width:min(1120px,calc(100% - 48px));margin-inline:auto}
.skip{position:absolute;left:16px;top:-64px;z-index:5;padding:8px 14px;background:var(--ink);color:var(--bg)}
.skip:focus{top:10px}
.kicker{font:600 13px/1 var(--mono);letter-spacing:.08em;color:var(--accent)}
.lede{color:var(--muted);font-size:18px}

/* site chrome */
.site-head{border-bottom:1px solid var(--line)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:64px}
.brand{display:inline-flex;align-items:center;gap:10px;color:var(--ink);font-weight:700;text-decoration:none;font-size:16px}
.brand-mark{display:grid;place-items:center;width:32px;height:32px;border-radius:7px;background:var(--accent);color:var(--bg);font:700 12px/1 var(--mono)}
.site-head nav{display:flex;align-items:center;gap:18px;font-size:15px}
.site-head nav a{color:var(--muted);text-decoration:none}
.site-head nav a:hover{color:var(--ink)}
.theme-toggle{display:grid;place-items:center;width:36px;height:36px;border:1px solid var(--line);border-radius:50%;background:transparent;cursor:pointer;padding:0}
.theme-toggle span{display:block;width:14px;height:14px;border-radius:50%;background:linear-gradient(90deg,var(--ink) 50%,transparent 50%);box-shadow:0 0 0 1.5px var(--ink)}
.site-foot{margin-top:72px;border-top:1px solid var(--line);padding:26px 0 32px;text-align:center;font-size:14px;color:var(--muted);line-height:1.8}
.site-foot a{color:inherit}

/* home */
.hero{padding:76px 0 60px;border-bottom:1px solid var(--line)}
.hero h1{margin-top:18px;font-size:clamp(32px,5.4vw,58px);line-height:1.2;font-weight:800;letter-spacing:-.01em;text-wrap:balance}
.hero .lede{margin-top:20px;max-width:36em}
.pipeline{display:grid;grid-template-columns:repeat(5,1fr);gap:0;margin-top:40px;padding:0;list-style:none;counter-reset:s}
.pipeline li{position:relative;padding:14px 16px;border:1px solid var(--line);border-right-width:0;background:var(--surface);counter-increment:s;animation:stage 7.5s infinite}
.pipeline li:last-child{border-right-width:1px;border-radius:0 8px 8px 0}
.pipeline li:first-child{border-radius:8px 0 0 8px}
.pipeline li:nth-child(2){animation-delay:1.5s}
.pipeline li:nth-child(3){animation-delay:3s}
.pipeline li:nth-child(4){animation-delay:4.5s}
.pipeline li:nth-child(5){animation-delay:6s}
.pipeline b{display:block;font:600 15px/1.3 var(--mono)}
.pipeline span{display:block;font-size:13px;color:var(--muted);line-height:1.5}
@keyframes stage{0%,20%{background:var(--accent-soft);box-shadow:inset 0 -3px 0 var(--accent)}24%,100%{background:var(--surface);box-shadow:inset 0 -3px 0 transparent}}
.hero-link{margin-top:16px;font-size:15px}
.posts{padding-top:48px}
.posts-head{display:flex;flex-wrap:wrap;align-items:baseline;justify-content:space-between;gap:10px 24px}
.section-title{font-size:26px;line-height:1.3}
.section-title small{font:500 14px var(--mono);color:var(--muted);margin-left:6px}
.topic-jump{display:flex;flex-wrap:wrap;gap:6px 16px;font-size:14px}
.topic-jump a{color:var(--muted)}
.topic{display:grid;grid-template-columns:200px minmax(0,1fr);gap:8px 32px;padding:30px 0;border-bottom:1px solid var(--line)}
.topic:last-child{border-bottom:0}
.topic>h2{font:600 15px/1.8 var(--mono);color:var(--accent)}
.post-list{list-style:none;padding:0;display:grid;gap:30px}
.post-row h3{font-size:21px;line-height:1.45;font-weight:700}
.post-row h3 a{color:var(--ink);text-decoration:none}
.post-row h3 a:hover{color:var(--accent);text-decoration:underline}
.post-row>p{margin-top:6px;color:var(--muted);font-size:16px;line-height:1.75}
.post-row .post-meta{margin-top:8px}
.post-meta{display:flex;flex-wrap:wrap;align-items:center;gap:6px 12px;font-size:13px;color:var(--muted)}
.badge{padding:0 8px;border-radius:4px;background:var(--accent-soft);color:var(--accent);line-height:1.8}

/* article */
.article-grid{display:grid;grid-template-columns:minmax(0,720px) 220px;justify-content:space-between;gap:56px;padding-top:52px}
.article-head h1{margin-top:14px;font-size:clamp(28px,4vw,40px);line-height:1.3;font-weight:800;text-wrap:balance}
.article-head .lede{margin-top:14px}
.article-head .post-meta{margin-top:14px}
.prose{margin-top:34px;border-top:1px solid var(--line)}
.prose>*{margin-top:18px}
.prose h2{margin-top:46px;font-size:25px;line-height:1.4;font-weight:750}
.prose h3{margin-top:30px;font-size:19px;font-weight:700}
.prose ul,.prose ol{padding-left:1.4em}
.prose li{margin-top:6px}
.prose code{font:.88em var(--mono);padding:.12em .36em;border-radius:4px;background:var(--code-bg);border:1px solid var(--line);overflow-wrap:anywhere}
.prose strong{font-weight:700;background:linear-gradient(transparent 62%,var(--mark) 62%)}
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:8px}
table{width:100%;border-collapse:collapse;font-size:15px;line-height:1.65}
th,td{padding:10px 14px;text-align:left;vertical-align:top;border-bottom:1px solid var(--line)}
td{min-width:6em}
th{font-weight:650;background:var(--code-bg);white-space:nowrap}
tr:last-child td{border-bottom:0}
.code{position:relative;border:1px solid var(--line);border-radius:8px;background:var(--code-bg);overflow:hidden}
.code figcaption{display:flex;align-items:center;justify-content:space-between;min-height:34px;padding:0 8px 0 14px;font:12px var(--mono);color:var(--muted);border-bottom:1px solid var(--line)}
.code pre{margin:0;padding:14px;overflow-x:auto;font:14px/1.7 var(--mono);tab-size:2}
.code pre code{font:inherit;padding:0;border:0;background:none;overflow-wrap:normal}
.copy{border:0;background:none;color:var(--muted);font:12px var(--sans);cursor:pointer;padding:4px 6px;border-radius:4px}
.copy:hover{color:var(--ink);background:var(--line)}
.tk-c{color:var(--tk-c);font-style:italic}.tk-s{color:var(--tk-s)}.tk-k{color:var(--tk-k)}.tk-n{color:var(--tk-n)}
.tk-f{color:var(--tk-f)}.tk-p{color:var(--tk-p)}.tk-t{color:var(--tk-t)}
.note{padding:12px 16px;border-left:3px solid var(--accent);background:var(--accent-soft);border-radius:0 6px 6px 0}
.toc-side{position:relative}
.toc{position:sticky;top:24px;font-size:14px;line-height:1.6}
.toc p{font:600 12px var(--mono);letter-spacing:.06em;color:var(--muted)}
.toc ol{list-style:none;margin-top:10px;padding:0;border-left:1px solid var(--line)}
.toc a{display:block;padding:5px 0 5px 12px;margin-left:-1px;border-left:2px solid transparent;color:var(--muted);text-decoration:none}
.toc a:hover{color:var(--ink)}
.toc a.is-current{color:var(--accent);border-left-color:var(--accent)}
.toc code{font:.92em var(--mono)}
.pager{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-top:52px}
.pager a{display:block;padding:14px 16px;border:1px solid var(--line);border-radius:8px;color:var(--ink);text-decoration:none;line-height:1.5;font-weight:600;font-size:15px}
.pager a:hover{border-color:var(--accent)}
.pager small{display:block;margin-bottom:2px;color:var(--muted);font-weight:400;font-size:12.5px}
.pager-next{grid-column:2;text-align:right}
.not-found{padding-top:96px;text-align:center}
.not-found h1{font-size:36px}
.not-found .lede{margin:12px 0}

/* demos */
.demo{margin-top:22px;padding:18px;border:1px solid var(--accent);border-radius:8px;background:var(--surface);font-size:15px;line-height:1.7}
.demo-fallback{color:var(--muted)}
.demo-title{font:600 12px var(--mono);letter-spacing:.06em;color:var(--accent);margin-bottom:10px}
.demo button.run{min-height:40px;padding:0 16px;border:0;border-radius:6px;background:var(--accent);color:var(--bg);font:600 14px var(--sans);cursor:pointer}
.demo button.alt{background:transparent;color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent)}
.demo-actions{display:flex;flex-wrap:wrap;gap:8px}
.demo-log{list-style:none;margin-top:12px;padding:0;display:grid;gap:6px;min-height:20px;font:14px var(--mono)}
.demo-log li{display:flex;justify-content:space-between;gap:12px;padding:6px 10px;border-radius:6px;background:var(--code-bg);animation:pop .3s both}
.demo-log li:nth-child(2){animation-delay:.12s}.demo-log li:nth-child(3){animation-delay:.24s}
.demo-log li:nth-child(4){animation-delay:.36s}.demo-log li:nth-child(5){animation-delay:.48s}
.demo-log small{color:var(--muted);font:12px var(--sans)}
@keyframes pop{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}
.demo-note{margin-top:10px;color:var(--muted);font-size:14px}
.layout-stage{height:64px;margin-top:12px;overflow:hidden;border:1px solid var(--line);border-radius:6px}
.layout-stage div{height:2px;background:var(--accent);width:40px;margin-bottom:1px}
.result-grid{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-top:12px}
.result-grid div{padding:10px 12px;border-radius:6px;background:var(--code-bg)}
.result-grid b{display:block;font:600 20px/1.4 var(--mono)}
.result-grid small{color:var(--muted)}
.flex-controls{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px}
.flex-controls label{display:grid;gap:4px;font:12px var(--mono);color:var(--muted)}
.flex-controls select{height:36px;padding:0 8px;border:1px solid var(--line);border-radius:6px;background:var(--bg);color:var(--ink);font:13px var(--mono)}
.flex-stage{display:flex;height:190px;margin-top:12px;padding:8px;gap:8px;border:1px dashed var(--muted);border-radius:6px;overflow:auto}
.flex-stage span{display:grid;place-items:center;border-radius:5px;background:var(--accent);color:var(--bg);font:600 13px var(--mono);padding:8px 14px;flex:none}
.flex-stage span:nth-child(1){min-height:34px}.flex-stage span:nth-child(2){min-height:64px;padding-inline:32px}
.flex-stage span:nth-child(3){min-height:46px}.flex-stage span:nth-child(4){min-height:80px;padding-inline:22px}
.flex-css{margin-top:10px;padding:10px 12px;border-radius:6px;background:var(--code-bg);font:13px/1.7 var(--mono);white-space:pre-wrap}
.contrast-controls{display:flex;flex-wrap:wrap;gap:14px}
.contrast-controls label{display:flex;align-items:center;gap:8px;font-size:14px}
.contrast-controls input{width:44px;height:32px;padding:0;border:1px solid var(--line);border-radius:6px;background:none;cursor:pointer}
.contrast-sample{margin-top:12px;padding:14px 16px;border-radius:6px;border:1px solid var(--line)}
.contrast-sample b{display:block;font-size:24px;line-height:1.4}
.contrast-result{display:flex;flex-wrap:wrap;gap:6px 16px;align-items:baseline;margin-top:12px}
.contrast-result strong{font:600 26px var(--mono)}
.pass{color:var(--tk-s)}.fail{color:var(--tk-t)}

@media (max-width:980px){
  .article-grid{grid-template-columns:minmax(0,1fr);gap:0;padding-top:36px}
  .toc-side{order:-1;margin-bottom:28px;padding:14px 16px;border:1px solid var(--line);border-radius:8px}
  .article{min-width:0}
  .toc{position:static}
}
@media (max-width:720px){
  body{font-size:16px}
  .wrap{width:calc(100% - 32px)}
  .hero{padding:48px 0 40px}
  .lede{font-size:16px}
  .pipeline{grid-template-columns:1fr}
  .pipeline li,.pipeline li:first-child,.pipeline li:last-child{border-right-width:1px;border-bottom-width:0;border-radius:0;display:flex;align-items:baseline;gap:10px;padding:9px 14px}
  .pipeline li:first-child{border-radius:8px 8px 0 0}
  .pipeline li:last-child{border-bottom-width:1px;border-radius:0 0 8px 8px}
  .topic{grid-template-columns:1fr;padding:24px 0}
  .post-row h3{font-size:19px}
  .pager{grid-template-columns:1fr}
  .pager-next{grid-column:auto}
  .result-grid{grid-template-columns:1fr}
  .code pre{font-size:13px}
}
@media (prefers-reduced-motion:reduce){
  *{animation:none!important;transition:none!important}
}