:root{
  --primary:#2563eb;--primary-light:#eff6ff;--primary-dark:#1e40af;
  --danger:#dc2626;--success:#16a34a;--warning:#f59e0b;--purple:#7c3aed;
  --bg:#f7f9fc;--card:#fff;--border:#e2e8f0;--text:#1e293b;--muted:#64748b;
  --radius:12px;
  --illo-max-h:13.6em;
}
*{box-sizing:border-box}
body{font-family:system-ui,sans-serif;margin:0;color:var(--text);background:var(--bg);line-height:1.7}
.wrap{max-width:880px;margin:0 auto;padding:16px 18px 80px;padding-top:calc(var(--chrome-pad, 72px) + 12px)}
.notes-chrome{position:fixed;top:0;left:0;width:100%;z-index:30;background:rgba(247,249,252,.97);border-bottom:1px solid var(--border);margin:0;pointer-events:none;transform-origin:0 0}
.notes-chrome .toolbar,.notes-chrome .toc{pointer-events:auto}
.toolbar{padding:6px 12px;display:flex;flex-wrap:nowrap;gap:6px;align-items:center;justify-content:space-between;overflow-x:auto}
.toolbar .left,.toolbar .right{display:flex;flex-wrap:nowrap;gap:8px;align-items:center;flex-shrink:0}
.back-link{color:var(--primary);text-decoration:none;font-size:12px;white-space:nowrap}
.seg{display:flex;border:1px solid var(--border);border-radius:6px;overflow:hidden;background:#fff}
.seg button,.seg a{border:0;background:#fff;padding:5px 8px;cursor:pointer;font-size:12px;font-weight:600;color:var(--muted);min-height:30px;line-height:1.2;touch-action:manipulation;text-decoration:none;display:inline-flex;align-items:center;white-space:nowrap}
.btn{border:1px solid var(--border);background:#fff;border-radius:6px;padding:5px 8px;cursor:pointer;font-size:12px;font-weight:600;text-decoration:none;color:var(--text);display:inline-flex;align-items:center;min-height:30px;line-height:1.2;white-space:nowrap;touch-action:manipulation}
.meta input{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:8px;font-size:16px}
.toc a{font-size:12px;padding:4px 10px;border-radius:999px;background:#fff;border:1px solid var(--border);color:var(--primary-dark);text-decoration:none;min-height:28px;display:inline-flex;align-items:center;touch-action:manipulation}
.seg button+button,.seg a+a,.seg button+a,.seg a+button{border-left:1px solid var(--border)}
.seg button.active,.seg a.active{background:var(--primary);color:#fff}
.btn.primary{background:var(--primary);color:#fff;border-color:var(--primary)}
#btn-draw.active{background:#f59e0b;color:#111;border-color:#d97706}
#btn-eraser.active{background:#fee2e2;border-color:#dc2626;color:#991b1b}
h1{font-size:26px;margin:8px 0 6px;line-height:1.3}
.kicker{margin:0 0 4px;font-size:13px;line-height:1.5;color:var(--muted)}
.lead{display:none}
.meta{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin:12px 0 20px}
.meta label{font-size:13px;color:var(--muted);display:block;margin-bottom:4px}
.toc{display:flex;flex-wrap:nowrap;gap:6px;margin:0;padding:2px 12px 8px;overflow-x:auto;-webkit-overflow-scrolling:touch}
section{background:#fff;border:1px solid var(--border);border-radius:var(--radius);padding:22px;margin:0 0 16px;overflow-x:auto}
section h2{margin:0 0 12px;font-size:20px;color:var(--primary-dark)}
section h3{margin:20px 0 8px;font-size:16px}
section h4{margin:14px 0 6px;font-size:14px}
p{margin:0 0 10px}
ul,ol{margin:0 0 12px;padding-left:1.25em}
li{margin:0 0 6px}
.def{background:#fff7ed;border-left:4px solid var(--warning);padding:10px 14px;border-radius:0 8px 8px 0;margin:12px 0}
.exam{background:var(--primary-light);border-left:4px solid var(--primary);padding:10px 14px;border-radius:0 8px 8px 0;margin:12px 0}
.exam p{margin:0 0 8px}
.exam p:last-child,.exam ul:last-child{margin-bottom:0}
.exam ul{margin:0 0 8px;padding-left:1.25em}
.exam h4{margin:12px 0 6px;font-size:14px;color:var(--primary-dark)}
.exam table{width:100%;margin:8px 0 12px;background:#fff;table-layout:fixed}
.exam table th:last-child,.exam table td:last-child{width:32%;text-align:center;font-weight:600}
.exam .two{margin:4px 0 0}
.exam .two .card{background:#fff}
.exam .two .card p{margin:8px 0 0}
.warn{background:#fef2f2;border-left:4px solid var(--danger);padding:10px 14px;border-radius:0 8px 8px 0;margin:12px 0}
.warn p{margin:0 0 8px}
.warn p:last-child{margin-bottom:0}
.eg{background:#f8fafc;border:1px solid var(--border);border-radius:10px;padding:12px 14px;margin:12px 0}
.eg .scene{margin:8px 0;padding:0;background:transparent;border:0}
.eg .scene img{max-height:var(--illo-max-h)}
.eg strong.lbl{display:inline-block;font-size:11px;letter-spacing:.04em;text-transform:uppercase;color:var(--primary-dark);margin-bottom:6px}
.flow{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin:12px 0}
.chip{background:#eef2ff;border:1px solid #c7d2fe;border-radius:8px;padding:8px 12px;font-size:13px;font-weight:600}
.arrow{color:var(--muted);font-weight:700}
.chain{display:flex;flex-direction:column;align-items:center;gap:0;margin:12px 0}
.chain > .chip{text-align:center;margin-top:4px}
.chain > .chip:first-child{margin-top:0}
.chain-row{display:grid;grid-template-columns:1fr 1fr;gap:10px;width:100%;max-width:560px}
.chain-row .chip{text-align:center;width:100%}
.chain-arr{
  width:2px;height:20px;margin:0 auto;background:var(--muted);
  color:transparent;font-size:0;line-height:0;position:relative
}
.chain-arr::after{
  content:"";position:absolute;left:50%;bottom:-1px;transform:translateX(-50%);
  border-left:4px solid transparent;border-right:4px solid transparent;border-top:6px solid var(--muted)
}
.chain-arrs.chain-row{
  height:22px;margin:0;justify-items:center;align-items:stretch;
  color:transparent;font-size:0;line-height:0;position:relative
}
.chain-arrs.chain-row > span{
  display:block;width:2px;height:100%;background:var(--muted);color:transparent;justify-self:center
}
.chain-link{width:100%;max-width:560px;height:36px;display:block;margin:0;overflow:visible}
.chip-start{background:#dbeafe;border-color:#93c5fd}
.chip-cost{background:#ecfdf5;border-color:#a7f3d0}
.chip-will{background:#fff7ed;border-color:#fdba74}
.chip-out{background:#f5f3ff;border-color:#ddd6fe}
.illo{display:grid;grid-template-columns:1fr 28px 1fr 28px 1fr;gap:8px;align-items:stretch;margin:14px 0 18px;padding:12px;background:#f8fafc;border:1px solid var(--border);border-radius:12px}
.illo-step{background:#fff;border:1px solid var(--border);border-radius:10px;padding:16px 14px;text-align:center}
.illo-step img{display:block;width:auto;max-width:100%;max-height:var(--illo-max-h);height:auto;margin:0 auto;border-radius:8px;object-fit:contain;background:#f8fafc}
.scene img{display:block;width:auto;max-width:100%;max-height:var(--illo-max-h);height:auto;margin:0 auto;border-radius:10px;background:#fff;object-fit:contain}
.scene-pair{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:8px 0 0;font-size:13px;font-weight:700;color:var(--primary-dark);text-align:center}
.illo-step .ttl{margin:8px 0 0;font-size:13px;font-weight:700;color:var(--primary-dark);line-height:1.35}
.illo-step .sub{margin:4px 0 0;font-size:12px;font-weight:500;color:var(--muted);line-height:1.4}
.illo-arr{display:flex;align-items:center;justify-content:center;color:var(--primary);font-size:22px;font-weight:700}
.tb-box .mark{margin:0 0 6px;font-size:11px;font-weight:700;letter-spacing:.04em;text-transform:uppercase;color:var(--primary-dark)}
.tb-box .why{margin:8px 0 0;font-size:14px;color:var(--muted)}
.scene{margin:14px 0 18px;padding:16px;background:#f8fafc;border:1px solid var(--border);border-radius:12px}
.scene svg{display:block;width:100%;max-width:640px;height:auto;margin:0 auto;overflow:visible}
.scene svg text{font-family:inherit;font-size:12px;fill:var(--text)}
.scene svg .muted{fill:var(--muted);font-size:11px}
.scene .cap{margin:8px 0 0;font-size:13px;color:var(--muted);text-align:center}
.grid4{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:12px 0}
.grid4 .cell{background:#fff;border:1px solid var(--border);border-radius:10px;padding:16px 14px;text-align:center;font-size:13px}
.grid4 .cell img{display:block;width:auto;max-width:100%;max-height:var(--illo-max-h);height:auto;margin:0 auto 10px;border-radius:8px;object-fit:contain;background:#f8fafc}
.grid4 .cell strong{display:block;color:var(--primary-dark);margin:4px 0 2px}
.grid4 .cell .hint{color:var(--muted);font-size:12px}
.two{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:12px 0}
.card{border:1px solid var(--border);border-radius:10px;padding:12px 14px;background:#fafafa}
.card h4{margin:0 0 6px}
.micro{border-top:3px solid var(--primary)}
.macro{border-top:3px solid var(--warning)}
table{width:max-content;max-width:100%;border-collapse:collapse;margin:10px auto 14px;font-size:14px}
th,td{border:1px solid #dbe3ee;padding:8px 10px;vertical-align:top}
th{background:#eef2ff;text-align:center}
td{text-align:left}
table.cmp td,
table:has(tbody tr th):not(.tb-ans) td{text-align:center;vertical-align:middle}
table.cmp td:first-child{text-align:left}
table.cmp > thead > tr > th:first-child,
table.cmp > tbody > tr > th,
table:has(tbody tr th):not(.tb-ans) > thead > tr > th:first-child,
table:has(tbody tr th):not(.tb-ans) > tbody > tr > th{text-align:left;vertical-align:middle;white-space:nowrap}
.sep{width:1%;padding-left:6px;padding-right:6px;color:var(--muted);font-size:12px;font-weight:700;text-align:center;white-space:nowrap;vertical-align:middle}
td.dir{text-align:center;vertical-align:middle}
td.dir .ans{display:inline-block;min-width:1.6em;font-size:1.15em}
td.grp{font-weight:700;text-align:center;vertical-align:middle;background:#eef2ff}
tr.mb-why td{background:#f8fafc;font-size:13px;vertical-align:middle}
.chosen{background:#ede9fe}
.forgone{background:#ffedd5}
.other-opt{background:#f8fafc}
.tag{display:inline-block;font-size:12px;font-weight:700;padding:4px 8px;border-radius:6px;line-height:1.35}
.tag.chosen{background:#ede9fe;color:#5b21b6;border:1px solid #c4b5fd}
.tag.forgone{background:#ffedd5;color:#9a3412;border:1px solid #fdba74}
.tag.other{background:#f1f5f9;color:#475569;border:1px solid #cbd5e1}
.val-shift{font-weight:800;color:var(--primary-dark);white-space:nowrap}
.keep-note{margin:8px 0 0;padding:8px 12px;background:#fff7ed;border-left:4px solid var(--warning);border-radius:0 8px 8px 0;font-size:13px}
.think{margin:12px 0;padding:12px 14px;background:#fff;border:1px solid #fdba74;border-radius:10px}
.think h4{margin:0 0 10px;font-size:14px;color:#c2410c}
.think .step{margin:10px 0 6px;font-weight:800;color:#9a3412}
.think table{font-size:13px}
.think table th,.think table td{vertical-align:top}
.think-path{margin:8px 0;padding:10px 12px;background:#eff6ff;border-radius:8px}
.think-path p{margin:0 0 8px}
.think-path p:last-child{margin:0}
.case-q{font-weight:800;color:var(--primary-dark);margin:12px 0 8px}
.cost-low{display:inline-block;margin:4px 0 0;padding:2px 8px;border-radius:999px;background:#dbeafe;color:#1e40af;font-size:12px;font-weight:800}
td.lower{background:#eff6ff}
.tool-link{display:inline-flex;margin:8px 8px 4px 0;padding:10px 16px;background:var(--primary);color:#fff;border-radius:8px;text-decoration:none;font-size:14px;font-weight:700;min-height:44px;align-items:center;touch-action:manipulation}
.ans{color:#1d4ed8;font-weight:700;border-bottom:1px dotted #93c5fd}
.ans.arr-up{color:var(--success);border-bottom-color:#86efac}
.ans.arr-down{color:var(--danger);border-bottom-color:#fca5a5}
.ans.arr-same{color:var(--muted);border-bottom-color:#cbd5e1}
body.mode-blank td.dir .ans,body.mode-click td.dir .ans:not(.open){min-width:1.6em;text-align:center}
html.htms-student #btn-click,
html.htms-student #link-tb-ans,
html.htms-student .click-hint{display:none!important}
html.htms-student body:not([data-ink-key^="econ-"]) #btn-full{display:none!important}
body.mode-blank .ans,body.mode-click .ans:not(.open){color:transparent;border-bottom:1px solid #334155;min-width:5em;display:inline-block;user-select:none;line-height:1.35;vertical-align:bottom}
body.mode-blank .ans.wide,body.mode-click .ans.wide:not(.open){min-width:14em}
body.mode-click .ans{cursor:pointer;background:#eff6ff;border-radius:4px;padding:2px 8px;min-height:28px;touch-action:manipulation;-webkit-tap-highlight-color:rgba(37,99,235,.25)}
body.mode-click .ans.open{color:#1d4ed8;background:#dbeafe;border-bottom:1px solid #93c5fd}
body.mode-click .ans.open.arr-up{color:var(--success);background:#ecfdf5;border-bottom-color:#86efac}
body.mode-click .ans.open.arr-down{color:var(--danger);background:#fef2f2;border-bottom-color:#fca5a5}
body.mode-click .ans.open.arr-same{color:var(--muted);background:#f8fafc;border-bottom-color:#cbd5e1}
.click-hint{display:none;font-size:13px;color:var(--primary-dark);background:var(--primary-light);border-radius:8px;padding:8px 12px;margin:0 0 14px}
body.mode-click .click-hint{display:block}
.draw-hint{display:none;font-size:13px;color:#9a3412;background:#fff7ed;border-radius:8px;padding:8px 12px;margin:0 0 14px}
body.draw-on .draw-hint{display:block}
body.draw-on{user-select:none;-webkit-user-select:none;touch-action:none}
.draw-bar{display:flex;flex-wrap:nowrap;gap:4px;align-items:center;flex-basis:auto}
.draw-tools{display:none;flex-wrap:nowrap;gap:4px;align-items:center}
body.draw-on .draw-tools{display:flex}
.swatch{width:22px;height:22px;min-height:22px;border-radius:50%;border:2px solid #fff;box-shadow:0 0 0 1px var(--border);padding:0;cursor:pointer;touch-action:manipulation}
.swatch.active{box-shadow:0 0 0 3px var(--primary)}
#paper-frame{position:relative;width:100%;overflow:visible}
#notes-body{position:relative;margin:0 auto;container-type:inline-size;container-name:notes}
#ink{position:absolute;left:0;top:0;z-index:12;pointer-events:none;touch-action:none;overflow:visible}
.ink-print-host{position:relative}
.ink-print{position:absolute;left:0;top:0;width:100%;height:100%;pointer-events:none;z-index:12;overflow:hidden}
body.draw-on #ink{pointer-events:auto;cursor:crosshair}
body.draw-on #paper-frame{touch-action:none}
.paper-sheet{background:#fff;border:1px dashed #94a3b8;border-radius:var(--radius);min-height:85vh;margin:0 0 16px;padding:18px 20px}
.paper-sheet .paper-lab{margin:0;font-size:13px;color:var(--muted)}
.share-backdrop{position:fixed;inset:0;background:rgba(15,23,42,.4);z-index:39}
.share-sheet{position:fixed;left:50%;top:50%;transform:translate(-50%,-50%);z-index:40;background:#fff;border:1px solid var(--border);border-radius:12px;padding:18px;width:min(440px,calc(100vw - 28px));box-shadow:0 16px 48px rgba(15,23,42,.2)}
.share-sheet h3{margin:0 0 8px;font-size:18px}
.share-sheet p{margin:0 0 8px;color:var(--muted);font-size:14px}
.share-sheet .row{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}
.check{margin:8px 0}
.check label{display:flex;gap:8px;align-items:flex-start;font-size:14px}
.glossary{display:grid;grid-template-columns:1fr 1fr;gap:6px 18px;font-size:14px}
.glossary div{display:flex;justify-content:space-between;gap:8px;border-bottom:1px dotted var(--border);padding:4px 0}
.tb-box{margin:16px 0 0;padding:14px 16px;border-radius:12px;border:1px solid var(--border);background:#fff}
.tb-box h3{margin:0 0 10px;font-size:15px}
.tb-lab{display:inline-block;max-width:100%;font-size:11px;font-weight:800;letter-spacing:.04em;text-transform:uppercase;padding:3px 8px;border-radius:6px;margin:0 0 10px;line-height:1.4}
.tb-head{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin:0 0 10px}
.tb-head .tb-lab{margin:0}
.tb-pg{font-size:12px;font-weight:700;color:var(--muted);white-space:nowrap}
.tb-quiz{background:#eff6ff;border-color:#93c5fd}
.tb-quiz .tb-lab{background:#2563eb;color:#fff}
.tb-guided{background:#fff7ed;border-color:#fdba74}
.tb-guided .tb-lab{background:#ea580c;color:#fff}
.tb-public{background:#f5f3ff;border-color:#c4b5fd}
.tb-public .tb-lab{background:#6d28d9;color:#fff}
.rank-opts{margin:2px 0 10px;padding-left:1.5em;line-height:1.75}
.tb-box .q{margin:0 0 10px;padding:10px 12px;background:#fff;border:1px solid var(--border);border-radius:8px}
.tb-box .q:last-child{margin:0}
.tb-box .ans{white-space:normal}
body.mode-blank .tb-box .ans,
body.mode-click .tb-box .ans:not(.open){display:block;min-width:100%;min-height:2.4em}
.tb-ans{width:100%;margin:12px 0 0;font-size:14px}
.tb-ans th{background:#fff7ed;color:#9a3412;font-size:13px;font-weight:800}
.tb-ans th:last-child,.tb-ans td:last-child{width:34%;background:#fffbeb;color:#9a3412;font-size:13px;font-weight:600}
.tb-ans td:last-child{color:#7c2d12;font-weight:500}
.tb-ans .part{font-weight:800;color:#c2410c;margin:0 0 4px}
.footer-note{font-size:12px;color:var(--muted);margin-top:20px}
.en[hidden],.zh[hidden]{display:none!important}
body.en svg .zh,body:not(.en) svg .en{display:none!important}
body.en svg .en,body:not(.en) svg .zh{display:inline!important}
@media(max-width:900px){
  .toolbar,.notes-chrome .toc{padding-left:8px;padding-right:8px}
}
@container notes (max-width:720px){
  .two,.meta,.glossary{grid-template-columns:1fr}
  h1{font-size:22px}
  section{padding:16px}
  .illo{grid-template-columns:1fr}
  .illo-arr{transform:rotate(90deg);height:22px}
  .grid4{grid-template-columns:1fr}
}
@page{size:A4;margin:20mm 22mm}
@media print{
  body{background:#fff;-webkit-print-color-adjust:exact;print-color-adjust:exact}
  .toolbar,.notes-chrome,.tool-link,.no-print,.lead,.footer-note,#extra-pages{display:none!important}
  .wrap{max-width:none;padding:0!important}
  section{break-inside:auto;border:1px solid #ccc;margin-bottom:12px;padding:18px 20px}
  .def,.exam,.warn,.eg,.tb-box,.tb-ans,.think,table,.scene,.illo,.grid4,.two,.chain{break-inside:avoid}
  h2,h3{break-after:avoid}
  .illo-step img,.scene img,.grid4 .cell img{max-width:100%;max-height:var(--illo-max-h);width:auto;height:auto}
  body.mode-blank .ans,body.mode-click .ans:not(.open){color:transparent;border-bottom:1px solid #000}
  body.mode-click .ans.open{color:#1d4ed8}
  body.mode-click .ans.open.arr-up,.ans.arr-up{color:var(--success)}
  body.mode-click .ans.open.arr-down,.ans.arr-down{color:var(--danger)}
  body.mode-click .ans.open.arr-same,.ans.arr-same{color:var(--muted)}
  a{color:inherit;text-decoration:none}
  #paper-frame{height:auto!important;overflow:visible}
  #notes-body{position:relative!important;transform:none!important;left:auto!important}
  section{overflow:visible}
  #ink,.ink-print-bands{display:none!important}
  .ink-print-host{position:relative!important;break-inside:avoid}
  .ink-print{position:absolute!important;left:0;top:0;width:100%;height:100%;pointer-events:none;z-index:12;overflow:hidden}
}