/* CSE One Learn. Tokens shared with cseone.in and Focus ("marigold"). */
:root{
  --bg:#faf7ef;--bg-2:#f5efe0;--surface:#fff;--ink:#1f1c16;--ink-2:#3d372d;--muted:#6c6457;
  --line:#ede6d5;--line-2:#e2d8c2;--accent:#ecb22e;--accent-soft:#fdf4d8;--accent-ink:#875b00;
  --on-accent:#2a1e02;--mark:linear-gradient(135deg,#f6c94f,#e3a51f);--live:#4f8a78;
  --shadow:0 1px 2px rgba(64,48,12,.035),0 8px 24px rgba(64,48,12,.045);
  --shadow-hover:0 2px 4px rgba(64,48,12,.05),0 22px 44px -18px rgba(64,48,12,.22);
  --radius:18px;--ease:cubic-bezier(.22,.8,.24,1)
}
@media (prefers-color-scheme:dark){:root{
  --bg:#15130f;--bg-2:#1d1a15;--surface:#211e18;--ink:#f6efe0;--ink-2:#d9cfbb;--muted:#a09682;
  --line:#2e2a22;--line-2:#3c362b;--accent:#f0bb3d;--accent-soft:#3a2e12;--accent-ink:#f5c95e;--live:#6fb9a3;
  --shadow:0 1px 2px rgba(0,0,0,.3),0 14px 34px -14px rgba(0,0,0,.6);
  --shadow-hover:0 2px 4px rgba(0,0,0,.35),0 24px 48px -18px rgba(0,0,0,.7)
}}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--ink);font:400 16px/1.65 "Plus Jakarta Sans",ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;-webkit-font-smoothing:antialiased;overflow-x:hidden}
a{color:inherit;text-decoration:none}
h1,h2{letter-spacing:-.02em;line-height:1.15;margin:0}
em{font-family:Fraunces,Georgia,serif;font-style:italic;font-weight:500;color:var(--accent-ink)}
:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:6px}

/* header */
.top{position:sticky;top:0;z-index:15;display:flex;align-items:center;gap:14px;height:64px;padding:0 22px;background:color-mix(in srgb,var(--bg) 88%,transparent);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid var(--line)}
.menu{display:none;place-items:center;width:40px;height:40px;border:1px solid var(--line-2);border-radius:12px;background:var(--surface);color:var(--ink);cursor:pointer}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;white-space:nowrap}
.brand b{color:var(--accent-ink);font-weight:800}
.mark{display:grid;place-items:center;width:34px;height:34px;border-radius:10px;background:var(--mark);color:var(--on-accent);font-size:13px;font-weight:800;box-shadow:inset 0 -1px 0 rgba(0,0,0,.08)}
.search-open{flex:1;max-width:420px;margin-left:auto;margin-right:auto;display:flex;align-items:center;gap:10px;font:inherit;font-size:14px;color:var(--muted);background:var(--surface);border:1px solid var(--line-2);border-radius:999px;padding:8px 14px;cursor:pointer;text-align:left}
.search-open span{flex:1}
.search-open kbd{font:600 11px/1 ui-monospace,monospace;border:1px solid var(--line-2);border-radius:5px;padding:3px 6px;color:var(--muted)}
.search-open:hover{border-color:var(--accent)}
.links{display:flex;gap:18px;align-items:center;font-size:14px;font-weight:600;color:var(--ink-2);white-space:nowrap}
.links a:hover{color:var(--accent-ink)}
.acct{border:1px solid var(--line-2);border-radius:999px;padding:6px 14px;background:var(--surface)}
.acct.in{background:var(--accent-soft);border-color:transparent;color:var(--accent-ink)}

/* three panes: syllabus map | page | on this page */
.shell{display:grid;grid-template-columns:300px minmax(0,1fr);min-height:calc(100vh - 64px)}
.shell.has-ctx{grid-template-columns:300px minmax(0,1fr) 250px}
.main{min-width:0;padding:8px clamp(20px,4vw,56px) 0}
.main>*{max-width:780px}
.side{position:sticky;top:64px;height:calc(100vh - 64px);display:flex;flex-direction:column;gap:12px;padding:22px 14px 16px 18px;border-right:1px solid var(--line);background:var(--bg-2)}
.side-head{display:flex;justify-content:space-between;align-items:flex-start;padding:0 4px}
.side-head h2{font-size:19px;font-weight:800}
.eyebrow{display:block;font-size:11px;font-weight:800;letter-spacing:.1em;text-transform:uppercase;color:var(--accent-ink);margin-bottom:3px}
.side-close{display:none;border:0;background:none;font-size:26px;line-height:1;color:var(--muted);cursor:pointer}
.tree-filter{font:inherit;font-size:14px;width:100%;border:1px solid var(--line-2);border-radius:10px;background:var(--surface);color:var(--ink);padding:9px 12px;outline:none}
.tree-filter:focus{border-color:var(--accent)}
.tree-wrap{flex:1;overflow:auto;margin:0 -6px;padding:0 6px 10px;scrollbar-width:thin;font-size:14px}
.tree-stage{margin:16px 4px 6px;font-size:11px;font-weight:800;letter-spacing:.11em;text-transform:uppercase;color:var(--muted)}
.tree-stage:first-child{margin-top:4px}
.tree-stage a:hover{color:var(--accent-ink)}
.tree,.tree ul{list-style:none;margin:0;padding:0}
.tree ul{margin-left:13px;padding-left:9px;border-left:1px solid var(--line-2)}
.tree summary{position:relative;display:flex;align-items:center;gap:6px;list-style:none;cursor:pointer;border-radius:8px;padding:5px 8px 5px 22px;color:var(--ink-2)}
.tree summary::-webkit-details-marker{display:none}
.tree summary::before{content:"";position:absolute;left:8px;top:15px;width:6px;height:6px;margin-top:-4px;border-right:1.6px solid var(--muted);border-bottom:1.6px solid var(--muted);transform:rotate(-45deg);transition:transform .15s}
.tree details[open]>summary::before{transform:rotate(45deg);margin-top:-5px}
.tree summary a{flex:1;min-width:0}
.tree summary:hover,.tree .leaf:hover{background:var(--surface);color:var(--ink)}
.tree .n{font-size:11px;font-weight:700;color:var(--muted);background:var(--surface);border:1px solid var(--line);border-radius:999px;padding:0 6px;line-height:17px}
.tree .leaf{display:block;border-radius:8px;padding:5px 8px 5px 10px;color:var(--ink-2);line-height:1.4}
.tree [aria-current],.tree-stage [aria-current]{color:var(--accent-ink);font-weight:750}
.tree .leaf[aria-current]{background:var(--accent-soft)}
.tree summary:has(>a[aria-current]){background:var(--accent-soft)}
.tree li.hit>.leaf,.tree li.hit>details>summary{background:var(--surface)}
.tree-empty{color:var(--muted);padding:8px}
.scope-card{display:flex;gap:10px;align-items:flex-start;border:1px solid var(--line);background:var(--surface);border-radius:12px;padding:11px 12px;font-size:12.5px;color:var(--muted)}
.scope-card strong{display:block;color:var(--ink);font-size:13px}
.scope-card p{margin:2px 0 0;line-height:1.45}
.dot{flex:0 0 8px;height:8px;margin-top:5px;border-radius:50%;background:var(--live);box-shadow:0 0 0 3px color-mix(in srgb,var(--live) 22%,transparent)}
.ctx{position:sticky;top:64px;height:calc(100vh - 64px);overflow:auto;padding:34px 20px 20px 8px;font-size:14px}
.ctx-sec{margin-bottom:26px}
.toc{display:flex;flex-direction:column;border-left:1px solid var(--line-2)}
.toc a{padding:5px 12px;margin-left:-1px;border-left:2px solid transparent;color:var(--muted);font-weight:600}
.toc a:hover{color:var(--ink)}
.toc a.on{color:var(--accent-ink);border-left-color:var(--accent)}
.go-mini{display:flex;flex-direction:column;gap:4px;border:1px solid var(--line);background:var(--surface);border-radius:12px;padding:10px 12px;margin-top:8px;font-weight:600;line-height:1.35}
.go-mini:hover{border-color:var(--accent)}
.go-mini .tag{align-self:flex-start;min-width:0}

/* home */
.hero{padding:44px 0 26px}
.kicker{margin:0 0 10px;font-size:12.5px;font-weight:700;letter-spacing:.09em;text-transform:uppercase;color:var(--accent-ink)}
.hero h1{font-size:clamp(34px,6vw,58px);font-weight:800}
.lede{font-size:18px;color:var(--ink-2);margin:18px 0 26px;max-width:640px}
.lede a{color:var(--accent-ink);text-decoration:underline}
.big-search{display:flex;align-items:center;gap:12px;width:100%;max-width:560px;font:inherit;font-size:16px;color:var(--muted);background:var(--surface);border:1px solid var(--line-2);border-radius:16px;padding:16px 18px;box-shadow:var(--shadow);cursor:pointer;text-align:left;transition:border-color .2s,box-shadow .2s}
.big-search:hover{border-color:var(--accent);box-shadow:var(--shadow-hover)}
.stage{margin:34px 0;padding-top:26px;border-top:1px solid var(--line)}
.stage-head{display:grid;grid-template-columns:minmax(0,1fr);gap:6px;align-items:baseline;margin-bottom:16px}
.stage-head h2{font-size:26px}
.stage-head h2 a:hover{color:var(--accent-ink)}
.stage-head p{margin:0;color:var(--muted);font-size:15px}
.papers{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:12px}
.papers a{display:flex;flex-direction:column;gap:4px;height:100%;background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:16px 18px;box-shadow:var(--shadow);transition:transform .25s var(--ease),box-shadow .25s,border-color .25s}
.papers a:hover{transform:translateY(-2px);box-shadow:var(--shadow-hover);border-color:var(--line-2)}
.papers .t{font-weight:700;font-size:16px;line-height:1.35}
.count{font-size:13px;color:var(--muted);font-weight:500}

/* node page */
.crumbs{display:flex;flex-wrap:wrap;gap:6px;font-size:13.5px;color:var(--muted);padding-top:18px}
.crumbs a:hover{color:var(--accent-ink)}
.crumbs span{opacity:.5}
.node{padding:18px 0 10px}
.node section,.next{scroll-margin-top:84px}
.node h1{font-size:clamp(30px,5vw,46px);font-weight:800;margin-bottom:22px}
.node section{margin:28px 0}
.node h2{font-size:13px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin-bottom:12px}
.node h2 span{color:var(--accent-ink);margin-left:4px}
.official{background:var(--accent-soft);border-radius:var(--radius);padding:20px 22px}
.official h2{color:var(--accent-ink)}
.official blockquote{margin:0 0 10px;font-family:Fraunces,Georgia,serif;font-size:20px;line-height:1.45;font-weight:500}
.official .src{margin:0;font-size:12.5px;color:var(--accent-ink);font-weight:600}
.scope p{margin:0;font-size:18px;color:var(--ink-2)}
.chips{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;gap:8px}
.chips li{background:var(--surface);border:1px solid var(--line-2);border-radius:999px;padding:6px 14px;font-size:14px;font-weight:600;color:var(--ink-2)}
.chips.links li{padding:0}
.chips.links a{display:block;padding:6px 14px}
.chips.links a:hover{color:var(--accent-ink)}
.cards{list-style:none;margin:0;padding:0;display:grid;gap:10px}
.cards a{display:grid;grid-template-columns:38px minmax(0,1fr);column-gap:12px;background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:16px 18px;box-shadow:var(--shadow);transition:transform .25s var(--ease),box-shadow .25s,border-color .25s}
.cards a:hover{transform:translateY(-2px);box-shadow:var(--shadow-hover);border-color:var(--line-2)}
.cards .num{grid-row:span 3;font:600 13px/1.9 ui-monospace,monospace;color:var(--accent-ink)}
.cards .t{font-weight:700;font-size:16.5px;line-height:1.35}
.cards .d{font-size:14.5px;color:var(--muted);margin-top:4px}
.cards .count{margin-top:6px}
.note{color:var(--muted);font-size:15px;margin:0 0 14px}
.opts{list-style:none;margin:0;padding:0;columns:3 220px;column-gap:24px}
.opts li{break-inside:avoid;padding:6px 0;border-bottom:1px solid var(--line);font-size:15px}
.opts a:hover{color:var(--accent-ink)}
.next{margin:34px 0;padding:20px;border:1px solid var(--line);border-radius:var(--radius);background:var(--bg-2)}
.next h2{font-size:13px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin-bottom:12px}
.go{display:grid;gap:8px}
.go a{display:flex;align-items:center;gap:12px;background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:12px 14px;font-weight:600;font-size:15px;transition:border-color .2s}
.go a:hover{border-color:var(--accent)}
.go a span:nth-child(2){flex:1}
.go b{color:var(--accent-ink)}
.tag{font-size:11.5px;font-weight:700;letter-spacing:.05em;text-transform:uppercase;color:var(--accent-ink);background:var(--accent-soft);border-radius:6px;padding:3px 8px;min-width:76px;text-align:center}
.pager{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:30px 0 10px}
.pager a{display:flex;flex-direction:column;gap:2px;border:1px solid var(--line);border-radius:12px;padding:12px 16px;font-weight:600;font-size:15px;background:var(--surface)}
.pager a:hover{border-color:var(--line-2)}
.pager .nxt{text-align:right}
.pager small{font-size:12px;color:var(--muted);font-weight:600}

/* footer */
.foot{border-top:1px solid var(--line);margin-top:50px;padding:24px 0 40px;max-width:780px;font-size:13.5px;color:var(--muted)}
.foot p{margin:0 0 12px;max-width:720px}
.foot a{text-decoration:underline;text-decoration-color:var(--line-2)}
.foot-links{display:flex;flex-wrap:wrap;gap:18px}
.foot-links a{text-decoration:none;font-weight:600;color:var(--ink-2)}

/* search */
.search{position:fixed;inset:0;z-index:20;background:rgba(20,16,8,.35);backdrop-filter:blur(3px);display:flex;justify-content:center;align-items:flex-start;padding:10vh 16px 16px}
.search[hidden]{display:none}
.search-box{width:min(620px,100%);background:var(--surface);border-radius:18px;box-shadow:0 30px 80px -20px rgba(0,0,0,.45);overflow:hidden;display:flex;flex-direction:column;max-height:76vh}
.search-box input{font:inherit;font-size:17px;border:0;border-bottom:1px solid var(--line);padding:18px 20px;background:transparent;color:var(--ink);outline:none}
#results{list-style:none;margin:0;padding:6px;overflow:auto}
#results a{display:block;padding:10px 14px;border-radius:10px}
#results a b{display:block;font-weight:650}
#results a small{color:var(--muted);font-size:13px}
#results a.on,#results a:hover{background:var(--accent-soft)}
#results .empty{padding:14px;color:var(--muted)}
.search-hint{margin:0;padding:10px 20px;border-top:1px solid var(--line);font-size:12px;color:var(--muted)}

@media (max-width:1240px){
  .shell.has-ctx{grid-template-columns:280px minmax(0,1fr)}
  .shell{grid-template-columns:280px minmax(0,1fr)}
  .ctx{display:none}
}
@media (max-width:900px){
  .menu{display:grid}
  .shell,.shell.has-ctx{grid-template-columns:minmax(0,1fr)}
  .side{position:fixed;z-index:30;top:0;left:0;bottom:0;height:auto;width:min(340px,88vw);transform:translateX(-102%);transition:transform .28s var(--ease);box-shadow:0 0 60px -10px rgba(0,0,0,.35)}
  .side.open{transform:none}
  .side-close{display:block}
  .scrim{position:fixed;inset:0;z-index:25;background:rgba(20,16,8,.35)}
  .scrim[hidden]{display:none}
  .links a:not(.acct){display:none}
}
@media (max-width:640px){
  .top{padding:0 14px;gap:10px}
  .brand span:last-child{font-size:15px}
  .search-open{max-width:none;padding:8px 10px;flex:0 0 auto;margin-left:auto;margin-right:0;border-radius:12px}
  .search-open span,.search-open kbd{display:none}
  .main{padding:4px 18px 0}
  .hero{padding-top:26px}
  .lede{font-size:16.5px}
  .official blockquote{font-size:18px}
  .scope p{font-size:16.5px}
  .pager{grid-template-columns:minmax(0,1fr)}
  .pager .nxt{text-align:left}
  .opts{columns:2 140px}
  .search{padding-top:12px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important}}