:root{
  /* 页面级 */
  --bg:#0b0d12; --bg2:#12151d; --card:#161a24; --card2:#1c2130;
  --line:#252b39; --txt:#e6e9f2; --dim:#98a1b8; --dim2:#6f7994;
  --acc:#6ea8fe; --acc2:#a78bfa; --ok:#4ade80; --warn:#fbbf24; --danger:#f87171;
  --r:14px;

  /* Demo 级（供 demo 内联样式引用） */
  --d-hole:#0e121b;        /* 舞台凹槽 */
  --d-panel:#1c2130;       /* 卡片 / 面板 */
  --d-panel-2:#161a24;     /* 次级面板 */
  --d-chip:#121724;        /* 标签 / 输入底 */
  --d-track:#232b3a;       /* 轨道 / hover */
  --d-border:#2b3348;      /* 边框 */
  --d-text:#e6e9f2;        /* 主文字 */
  --d-dim:#98a1b8;         /* 次文字 */
  --d-dim-2:#6f7994;       /* 弱文字 */
  --d-inv-text:#0b0d12;    /* 主色底上的文字 */
  --d-accent:#6ea8fe;
  --d-accent-2:#a78bfa;
  --d-ok:#4ade80;
  --d-warn:#fbbf24;
  --d-danger:#f87171;
  --d-shadow:0 10px 26px rgba(0,0,0,.35);
}

[data-theme="light"]{
  --bg:#f4f6fa; --bg2:#ffffff; --card:#ffffff; --card2:#f7f9fc;
  --line:#dde3ee; --txt:#1a2233; --dim:#5b6780; --dim2:#8a94a8;
  --acc:#2563eb; --acc2:#7c3aed; --ok:#16a34a; --warn:#d97706; --danger:#dc2626;

  --d-hole:#eaeef5;
  --d-panel:#ffffff;
  --d-panel-2:#f7f9fc;
  --d-chip:#eef2f8;
  --d-track:#e2e8f2;
  --d-border:#d5dcea;
  --d-text:#1a2233;
  --d-dim:#5b6780;
  --d-dim-2:#8a94a8;
  --d-inv-text:#ffffff;
  --d-accent:#2563eb;
  --d-accent-2:#7c3aed;
  --d-ok:#16a34a;
  --d-warn:#d97706;
  --d-danger:#dc2626;
  --d-shadow:0 10px 24px rgba(20,30,60,.12);
}

*{box-sizing:border-box}
html,body{margin:0;padding:0}
body{
  background:var(--bg);
  color:var(--txt);
  font:14px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI","PingFang SC","Microsoft YaHei",sans-serif;
  min-height:100vh;
}
code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:12px;color:var(--acc)}

/* ---------- topbar ---------- */
.topbar{position:sticky;top:0;z-index:50;background:var(--bg2);border-bottom:1px solid var(--line)}
.topbar-main{display:flex;flex-wrap:wrap;gap:16px;align-items:flex-end;justify-content:space-between;padding:16px 24px 12px}
.titles h1{margin:0;font-size:20px;letter-spacing:.3px}
.titles p{margin:4px 0 0;color:var(--dim);font-size:12.5px}
.controls{display:flex;gap:12px;align-items:center;flex-wrap:wrap}
#search{background:var(--card);border:1px solid var(--line);color:var(--txt);border-radius:9px;padding:7px 11px;width:230px;outline:none}
#search:focus{border-color:var(--acc)}
.switch{display:flex;gap:6px;align-items:center;color:var(--dim);font-size:12.5px;cursor:pointer;user-select:none}
.switch input{accent-color:var(--acc);width:15px;height:15px}
.count{color:var(--dim2);font-size:12px}
.catnav{display:flex;gap:8px;overflow-x:auto;padding:0 24px 12px;scrollbar-width:thin}
.catnav a{
  flex:0 0 auto;text-decoration:none;color:var(--dim);font-size:12.5px;
  padding:5px 12px;border:1px solid var(--line);border-radius:999px;background:var(--bg2);white-space:nowrap
}
.catnav a:hover{color:var(--txt);border-color:var(--acc)}

/* ---------- sections ---------- */
main{padding:8px 24px 60px}
section{margin:34px 0 0;scroll-margin-top:120px}
.sec-head{display:flex;align-items:baseline;gap:12px;flex-wrap:wrap;margin:0 0 14px}
.sec-head h2{margin:0;font-size:16.5px}
.sec-head .en{color:var(--dim2);font-size:12px;letter-spacing:.4px;text-transform:uppercase}
.sec-head .desc{color:var(--dim);font-size:12.5px}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(340px,1fr));gap:16px}

/* ---------- card ---------- */
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);overflow:hidden;display:flex;flex-direction:column}
.card-head{padding:12px 14px 10px;border-bottom:1px solid var(--line)}
.card-head .row1{display:flex;align-items:baseline;gap:8px;flex-wrap:wrap}
.idx{color:var(--dim2);font-size:11px;font-family:ui-monospace,monospace}
.zh{font-weight:600;font-size:14px}
.en{color:var(--acc);font-size:12px;font-family:ui-monospace,monospace}
.card-head p{margin:6px 0 0;color:var(--dim);font-size:12.3px;min-height:2.2em}
.stage{position:relative;background:var(--d-hole);padding:14px;display:flex;align-items:center;justify-content:center;min-height:210px;overflow:hidden}
.card-foot{padding:8px 14px 11px;color:var(--dim2);font-size:11.5px;border-top:1px solid var(--line)}
.card.hide{display:none}

/* ---------- shared demo primitives ---------- */
.d-btn{background:var(--card2);color:var(--txt);border:1px solid var(--line);border-radius:9px;padding:6px 12px;font-size:12.5px;cursor:pointer}
.d-btn:hover{border-color:var(--acc)}
.d-btn.primary{background:var(--acc);color:var(--d-inv-text);border-color:transparent;font-weight:600}
.d-btn:disabled{opacity:.5;cursor:not-allowed}
.d-hint{position:absolute;left:12px;bottom:8px;color:var(--d-dim-2);font-size:11px;pointer-events:none}
.d-val{font-family:ui-monospace,monospace;font-size:11px;color:var(--dim)}
.d-panel{background:var(--card2);border:1px solid var(--line);border-radius:11px;padding:10px 12px}
.d-row{display:flex;gap:8px;align-items:center;flex-wrap:wrap}
.d-tag{font-size:11.5px;color:var(--dim);background:var(--d-chip);border:1px solid var(--line);border-radius:999px;padding:3px 9px}
.grab{cursor:grab;touch-action:none;user-select:none}
.grab:active{cursor:grabbing}

/* ---------- intro (static, SEO-friendly) ---------- */
.gh-link{display:inline-flex;align-items:center;text-decoration:none;gap:4px}
.intro{margin:22px 24px 0;padding:18px 20px;background:var(--card);border:1px solid var(--line);border-radius:var(--r)}
.intro h2{margin:0 0 10px;font-size:16px;line-height:1.5}
.intro p{margin:0 0 10px;color:var(--dim);font-size:13px;line-height:1.75}
.intro-cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:10px 18px;margin-top:12px}
.intro-cols div{font-size:12px;color:var(--dim);line-height:1.85}
.intro-cols strong{color:var(--txt);font-size:12.5px}
.intro-links{margin:14px 0 0 !important;font-size:12.5px}
.intro-links a,.foot a{color:var(--acc);text-decoration:none}
.intro-links a:hover,.foot a:hover{text-decoration:underline}

/* ---------- bilingual (zh default, en on [data-lang="en"]) ---------- */
.i-en{display:none}
[data-lang="en"] .i-en{display:block}
[data-lang="en"] .i-zh{display:none}

/* ---------- responsive ---------- */
@media (max-width:900px){
  main{padding:8px 14px 48px}
  .intro{margin:16px 14px 0;padding:15px 16px}
  .intro-cols{grid-template-columns:1fr}
  .topbar-main{padding:14px 14px 10px}
  .catnav{padding:0 14px 10px}
  #search{width:170px}
}
@media (max-width:560px){
  main{padding:8px 10px 40px}
  .intro{margin:14px 10px 0;padding:14px 14px}
  .intro h2{font-size:15px}
  .grid{grid-template-columns:1fr}
}
.foot{padding:26px 24px 40px;color:var(--dim2);font-size:11.5px;line-height:1.9;text-align:center}