:root{color-scheme:light;--ink:#282820;--muted:#6a6a5e;--paper:#fffef9;--line:#dfdfd2;--accent:#305e50;--soft:#eef3ed}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:#f4f2e9;color:var(--ink);font-family:"PingFang SC","Microsoft YaHei",system-ui,sans-serif;font-size:17px;line-height:1.85}a{color:var(--accent);text-underline-offset:4px}a:hover{color:#173f32}a:focus-visible,button:focus-visible,.table-wrap:focus-visible{outline:3px solid #a75f28;outline-offset:4px}header{max-width:1240px;margin:auto;padding:22px 32px;display:flex;align-items:center;justify-content:space-between;gap:20px;flex-wrap:wrap}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--ink);font-weight:600}.brand img{object-fit:contain}.header-actions{display:flex;gap:20px;align-items:center;flex-wrap:wrap;font-size:15px}button{font:inherit;color:var(--accent);background:var(--paper);border:1px solid var(--line);border-radius:6px;padding:6px 14px;cursor:pointer}.layout{max-width:1240px;margin:0 auto;padding:10px 32px 48px;display:grid;grid-template-columns:238px minmax(0,1fr);gap:32px}aside{align-self:start;position:sticky;top:24px;max-height:calc(100vh - 48px);overflow:auto;padding:16px 0}aside h2{font-size:15px;margin:0 0 12px;padding:0 12px;color:var(--muted)}.toc a{display:block;padding:7px 12px;font-size:14px;line-height:1.5;text-decoration:none;border-left:2px solid transparent}.toc a:hover,.toc a[aria-current="location"]{background:var(--soft);border-color:var(--accent)}.toc small{display:block;font-size:12px;color:var(--muted);margin-top:3px}main{min-width:0}.guide-section{background:var(--paper);border:1px solid var(--line);border-radius:10px;padding:30px 36px;margin-bottom:24px;scroll-margin-top:24px}.intro{border-top:4px solid var(--accent)}.kicker{font-size:14px;color:var(--accent);margin:0 0 8px}h1{font-size:34px;line-height:1.45;margin:0 0 20px;font-weight:650;letter-spacing:-.5px}h1 span{white-space:nowrap}h2{font-size:23px;line-height:1.55;margin:0 0 20px;font-weight:650}h3{font-size:18px;margin:28px 0 12px;padding:8px 12px;background:var(--soft);border-radius:4px;font-weight:600}p{margin:12px 0}ol,ul{padding-left:1.5em;margin:12px 0}li{padding-left:4px;margin:7px 0}.table-wrap{overflow-x:auto;margin:18px 0}table{border-collapse:collapse;width:100%;font-size:15px;line-height:1.65;text-align:left}th,td{padding:11px 12px;border-bottom:1px solid var(--line);vertical-align:top}th{background:var(--soft);font-weight:600}td:first-child{white-space:nowrap}footer{max-width:1240px;margin:auto;padding:0 32px 32px;font-size:14px;color:var(--muted);text-align:center}.print-note{display:none}
@media(max-width:900px){.layout{grid-template-columns:190px minmax(0,1fr);gap:20px;padding-inline:20px}.guide-section{padding:24px}header{padding-inline:20px}}
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@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}
@media print{body{background:white;color:black;font-size:11pt;line-height:1.7}header,aside,.header-actions{display:none}.layout{display:block;padding:0;max-width:none}.guide-section{border:0;border-radius:0;padding:0;margin:0 0 20px}.lesson{break-before:page}.intro{border:0}h1{font-size:22pt}h2{font-size:17pt}h3{font-size:12pt;background:transparent;padding:0;break-after:avoid}h2,h3{break-after:avoid}li,tr{break-inside:avoid}.table-wrap{overflow:visible}table{font-size:10pt}thead{display:table-header-group}a{color:black;text-decoration:none}footer{padding:12px 0;font-size:10pt}.print-note{display:block;color:#444;font-size:10pt}@page{size:A4;margin:18mm}}