:root{
  --paper:#F4ECD9; --paper-2:#EFE5CE; --card:#FBF6E9;
  --ink:#241E1B; --ink-soft:#5c534b; --line:#d8c9a8;
  --seal:#B23A2E; --gold:#B67A28;
  --pA:#33506E; --pB:#4A7A5E; --pC:#B23A2E; --pD:#B67A28; --pE:#6D3B8E;
  --shadow:0 1px 2px rgba(40,30,20,.08),0 6px 20px rgba(40,30,20,.06);
  --serif:"Noto Serif TC","Songti TC","Source Han Serif TC",Georgia,"SimSun",serif;
  --sans:"Noto Sans TC","PingFang TC","Microsoft JhengHei","Heiti TC",system-ui,sans-serif;
}
@media (prefers-color-scheme:dark){
  :root{ --paper:#15161C; --paper-2:#1b1d25; --card:#20222c; --ink:#ECE6DA; --ink-soft:#a49b8d; --line:#33323d; --seal:#E0705F; --gold:#D9A24B; --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px rgba(0,0,0,.35); }
}
:root[data-theme="dark"]{ --paper:#15161C; --paper-2:#1b1d25; --card:#20222c; --ink:#ECE6DA; --ink-soft:#a49b8d; --line:#33323d; --seal:#E0705F; --gold:#D9A24B; --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px rgba(0,0,0,.35); }
:root[data-theme="light"]{ --paper:#F4ECD9; --paper-2:#EFE5CE; --card:#FBF6E9; --ink:#241E1B; --ink-soft:#5c534b; --line:#d8c9a8; --seal:#B23A2E; --gold:#B67A28; --shadow:0 1px 2px rgba(40,30,20,.08),0 6px 20px rgba(40,30,20,.06); }

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--sans);line-height:1.7;
  background-image:radial-gradient(circle at 10% 4%,rgba(178,58,46,.045),transparent 38%),radial-gradient(circle at 92% 96%,rgba(51,80,110,.05),transparent 42%);}
a{color:var(--seal);text-decoration:none}
a:hover{text-decoration:underline}

.shell{display:grid;grid-template-columns:264px minmax(0,1fr);gap:0;max-width:1240px;margin:0 auto}

/* sidebar */
aside.side{position:sticky;top:0;align-self:start;height:100vh;overflow:auto;
  border-right:1px solid var(--line);padding:22px 16px 40px;background:var(--paper-2)}
.brand{display:block;margin-bottom:6px}
.brand .seal{display:inline-grid;place-content:center;width:44px;height:44px;border:2px solid var(--seal);border-radius:9px;color:var(--seal);font-family:var(--serif);font-weight:800;font-size:15px;transform:rotate(-2deg);box-shadow:inset 0 0 0 2px var(--paper-2),inset 0 0 0 3px var(--seal)}
.brand h1{font-family:var(--serif);font-size:19px;margin:12px 0 2px;line-height:1.25;font-weight:800}
.brand p{font-size:12px;color:var(--ink-soft);margin:0}
.navgroup{margin-top:20px}
.navgroup .lbl{font-size:11px;letter-spacing:2px;color:var(--ink-soft);text-transform:uppercase;font-weight:700;margin:0 0 7px 6px}
.navgroup a{display:block;padding:7px 11px;border-radius:8px;color:var(--ink);font-size:14px;margin-bottom:2px;border-left:3px solid transparent}
.navgroup a:hover{background:var(--card);text-decoration:none}
.navgroup a.active{background:var(--card);border-left-color:var(--seal);color:var(--seal);font-weight:700}

/* main */
main{padding:38px clamp(20px,4vw,56px) 90px;min-width:0}
.page{max-width:820px;margin:0 auto}
.crumb{font-size:12.5px;color:var(--ink-soft);margin-bottom:18px;letter-spacing:.5px}
.content{overflow-wrap:break-word}
.content h1{font-family:var(--serif);font-size:clamp(24px,3.6vw,34px);line-height:1.15;margin:.2em 0 .5em;text-wrap:balance;letter-spacing:.5px}
.content h2{font-family:var(--serif);font-size:clamp(19px,2.6vw,24px);margin:1.7em 0 .5em;padding-bottom:.28em;border-bottom:2px solid var(--line);letter-spacing:.5px}
.content h3{font-size:17px;margin:1.4em 0 .4em;color:var(--seal);font-weight:800}
.content h4{font-size:15px;margin:1.1em 0 .3em;font-weight:800}
.content p{margin:.7em 0}
.content ul,.content ol{margin:.6em 0;padding-left:1.4em}
.content li{margin:.28em 0}
.content strong{color:var(--ink);font-weight:800}
.content blockquote{margin:1em 0;padding:.7em 1em;border-left:4px solid var(--gold);background:var(--card);border-radius:0 8px 8px 0;color:var(--ink-soft)}
.content blockquote p{margin:.35em 0}
.content code{font-family:ui-monospace,"Cascadia Code",Consolas,monospace;background:var(--card);border:1px solid var(--line);border-radius:5px;padding:.08em .38em;font-size:.88em}
.content pre{background:var(--card);border:1px solid var(--line);border-radius:10px;padding:14px 16px;overflow-x:auto;line-height:1.6}
.content pre code{background:none;border:none;padding:0;font-size:.86em}
.content hr{border:none;border-top:1px solid var(--line);margin:2em 0}
.tablewrap{overflow-x:auto;margin:1.1em 0;border:1px solid var(--line);border-radius:10px}
.content table{border-collapse:collapse;width:100%;font-size:14px;background:var(--card)}
.content th,.content td{border:1px solid var(--line);padding:8px 11px;text-align:left;vertical-align:top}
.content thead th{background:var(--seal);color:#fff;font-weight:700;border-color:var(--seal)}
.content tbody tr:nth-child(even){background:color-mix(in srgb,var(--paper-2) 55%,transparent)}
.wl{color:var(--seal);font-weight:600}

/* home */
.hero{background:var(--seal);color:#fff;border-radius:18px;padding:clamp(26px,4vw,46px);margin-bottom:26px;box-shadow:var(--shadow);position:relative;overflow:hidden}
.hero h1{font-family:var(--serif);font-size:clamp(26px,4.6vw,44px);margin:0 0 12px;line-height:1.1;text-wrap:balance}
.hero .tag{font-size:clamp(14px,1.8vw,18px);opacity:.95;max-width:60ch;margin:0}
.hero .meta{margin-top:18px;display:flex;flex-wrap:wrap;gap:8px}
.hero .chip{background:rgba(255,255,255,.18);padding:5px 12px;border-radius:20px;font-size:12.5px;font-weight:600}
.flow{display:flex;flex-wrap:wrap;gap:6px;align-items:center;font-family:var(--serif);margin:6px 0 30px;color:var(--ink-soft);font-size:15px}
.flow .n{color:var(--ink);font-weight:700;background:var(--paper-2);border:1px solid var(--line);padding:4px 11px;border-radius:20px}
.flow .s{color:var(--seal);font-weight:800}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:14px}
.card{display:block;background:var(--card);border:1px solid var(--line);border-left:5px solid var(--c,var(--seal));border-radius:12px;padding:15px 16px;box-shadow:var(--shadow);color:var(--ink)}
.card:hover{text-decoration:none;transform:translateY(-2px);transition:transform .12s}
.card .k{font-family:var(--serif);font-weight:800;font-size:16px;margin-bottom:3px}
.card .d{font-size:13px;color:var(--ink-soft);line-height:1.5}
.sectlabel{font-size:12px;letter-spacing:2px;color:var(--ink-soft);text-transform:uppercase;font-weight:700;margin:30px 0 12px}

/* worksheet / seaturtle bespoke */
.ws{background:var(--card);border:1px solid var(--line);border-radius:14px;padding:20px 22px;margin:16px 0;box-shadow:var(--shadow);border-top:5px solid var(--c,var(--seal))}
.ws .wshead{display:flex;align-items:center;gap:12px;margin-bottom:10px}
.ws .num{background:var(--c,var(--seal));color:#fff;width:38px;height:38px;border-radius:9px;display:grid;place-content:center;font-family:var(--serif);font-weight:800}
.ws .wsh{font-family:var(--serif);font-size:19px;font-weight:800;margin:0}
.ws .wsub{font-size:13px;color:var(--ink-soft)}
.field{border-left:3px solid var(--line);padding:2px 0 2px 12px;margin:10px 0}
.field b{display:block;font-size:14.5px}
.field span{font-size:13px;color:var(--ink-soft)}
.stcard{background:var(--card);border:1px solid var(--line);border-left:5px solid var(--c);border-radius:12px;padding:14px 16px;margin:12px 0;box-shadow:var(--shadow)}
.stcard .stn{font-family:var(--serif);font-weight:800;color:var(--c);font-size:13px}
.stcard .stq{font-size:15.5px;font-weight:700;margin:3px 0 6px}
.stcard details{margin-top:6px;font-size:13.5px}
.stcard summary{cursor:pointer;color:var(--seal);font-weight:700}
.stcard .ans{color:var(--ink-soft);margin-top:5px}

footer.foot{border-top:1px solid var(--line);margin-top:40px;padding-top:16px;font-size:12.5px;color:var(--ink-soft);display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px}
.prevnext{display:flex;justify-content:space-between;gap:12px;margin-top:34px}
.prevnext a{flex:1;background:var(--card);border:1px solid var(--line);border-radius:10px;padding:12px 14px;font-size:13px}
.prevnext a.next{text-align:right}
.prevnext .k{color:var(--ink-soft);font-size:11px;display:block}

@media (max-width:860px){
  .shell{grid-template-columns:1fr}
  aside.side{position:sticky;top:0;height:auto;z-index:5;border-right:none;border-bottom:1px solid var(--line);padding:12px 14px}
  .brand{display:flex;align-items:center;gap:10px;margin-bottom:4px}
  .brand h1{font-size:16px;margin:0}
  .brand p{display:none}
  .navwrap{display:flex;gap:16px;overflow-x:auto;padding-bottom:4px}
  .navgroup{margin-top:10px;min-width:max-content}
  .navgroup a{display:inline-block;margin:0 2px}
  main{padding:22px 18px 70px}
}