:root{color-scheme:light;--ink:#17233b;--muted:#586578;--blue:#233d74;--accent:#b44029;--paper:#fcfcfa;--line:#dce2e9;--pale:#eef3fa}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,"PingFang SC","Microsoft YaHei",sans-serif;font-size:17px;line-height:1.85}a{color:var(--blue);text-decoration-thickness:1px;text-underline-offset:4px}button,input{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,input:focus-visible,summary:focus-visible{outline:3px solid #c25138;outline-offset:3px}h1,h2,h3{line-height:1.4;letter-spacing:-.02em}h1{font-family:"Songti SC","Noto Serif CJK SC",serif;font-size:40px;font-weight:700;margin:18px 0 28px}h2{font-size:25px;margin:42px 0 16px}h3{font-size:20px;margin:26px 0 12px}p{margin:14px 0 20px}#sidebar{position:fixed;inset:0 auto 0 0;width:286px;border-right:1px solid var(--line);background:#f2f5f8;padding:28px 22px;overflow-y:auto;font-size:14px}.brand{display:flex;align-items:center;gap:12px;color:var(--ink);text-decoration:none;font-size:19px;font-weight:650;line-height:1.6}.brand small{display:block;font-size:12px;font-weight:400;color:var(--muted);letter-spacing:.06em}.seal{display:grid;place-items:center;background:var(--accent);color:#fff;width:40px;height:44px;font-family:serif;font-size:26px;border-radius:2px}.search-label{display:block;margin-top:28px;font-size:13px;color:var(--muted)}#search{width:100%;padding:10px 11px;margin:5px 0 14px;background:#fff;border:1px solid #bac6d6;border-radius:5px;font-size:14px}.progress-label{display:flex;justify-content:space-between;color:var(--muted);font-size:13px}progress{width:100%;height:5px;accent-color:var(--blue);display:block;margin:8px 0 24px}.nav-group{margin-bottom:20px}.nav-group p{font-size:12px;letter-spacing:.06em;font-weight:650;color:var(--muted);margin:0 0 8px}.lesson-link{display:flex;align-items:flex-start;gap:9px;text-decoration:none;color:#47536a;padding:7px 8px;border-radius:4px;line-height:1.7;font-size:14px}.lesson-link:hover{background:#e4ebf6}.lesson-link.active{background:#dfe8f7;color:#1a3972;font-weight:650}.lesson-number{font-variant-numeric:tabular-nums;font-size:12px;opacity:.75;padding-top:1px}.tick{margin-left:auto;color:#236d54}.side-link{font-size:14px}.mobile-bar{display:none}main{margin-left:286px;max-width:1250px;padding:46px 7vw 36px}.breadcrumb{font-size:14px;color:var(--muted);display:flex;gap:12px;flex-wrap:wrap}.breadcrumb a{text-decoration:none}.eyebrow{font-size:13px;letter-spacing:.13em;color:var(--blue);font-weight:650}.chapter-head{border-bottom:1px solid var(--line);padding:30px 0 6px;margin-bottom:28px}.opening{display:grid;grid-template-columns:1.3fr 1fr;align-items:center;gap:44px;margin:45px 0 50px}.opening h1{font-size:58px;line-height:1.35;margin:18px 0}.opening p{max-width:430px;color:var(--muted)}.primary{display:inline-block;background:var(--blue);color:white;text-decoration:none;padding:11px 21px;border-radius:4px;margin:6px 14px 10px 0;font-size:16px}.text-link{font-size:14px;display:inline-block}.book-note{background:#1c304f;color:#f7f8fb;padding:30px 26px;border-top:5px solid #b65a3b}.book-note>span{font-size:14px;color:#c7d4e7}.book-note ol{padding-left:22px;line-height:2.6;font-family:"Songti SC",serif;font-size:23px}.book-note small{font-size:13px;color:#c7d4e7}.process{display:flex;gap:12px;align-items:center;flex-wrap:wrap;margin:22px 0}.process span{border-bottom:2px solid #9cacc4;padding:8px 9px;font-size:16px}.process b{font-size:15px;color:var(--muted)}.quickstart{border:1px solid var(--line);padding:2px 26px 18px;margin-top:35px}.quickstart h2{margin-top:24px}.curriculum{display:grid;grid-template-columns:1fr 1fr;gap:22px 36px}.curriculum h3{font-size:16px;border-bottom:1px solid var(--line);padding-bottom:11px}.curriculum a{display:flex;gap:14px;padding:6px 0;text-decoration:none;font-size:15px}.curriculum a span{color:var(--muted);font-size:12px}.curriculum a:hover{text-decoration:underline}code{font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.9em;background:#eaf0f7;padding:2px 5px;border-radius:3px;overflow-wrap:anywhere}.code-block{margin:22px 0;border:1px solid #c9d4e1;border-radius:5px;overflow:hidden;background:#f3f6fa}.code-head{padding:7px 14px;border-bottom:1px solid #d8e0ea;display:flex;justify-content:space-between;align-items:center;font-size:12px;color:var(--muted)}.copy{border:1px solid #b7c5d9;background:transparent;border-radius:3px;padding:2px 10px;font-size:13px;color:var(--blue)}pre{overflow:auto;padding:17px 19px;margin:0;font-size:15px;line-height:1.7;tab-size:4}pre code{background:none;padding:0;border-radius:0;overflow-wrap:normal;font-size:inherit}.note{border-left:3px solid var(--accent);padding:15px 20px;background:#f8eee8;margin:24px 0;font-size:16px}.table-scroll{overflow-x:auto;margin:24px 0}table{border-collapse:collapse;width:100%;font-size:15px}th,td{padding:11px 14px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}th{background:#edf2f8;white-space:nowrap}.lesson-body ul{padding-left:24px}.lesson-body li{margin:9px 0}.lesson-body{max-width:880px}.source-panel,details.answer{padding:16px 20px;border:1px solid var(--line);margin:30px 0;background:#fff}summary{cursor:pointer;font-weight:600;color:var(--blue)}.finish{margin-top:50px;border-top:2px solid var(--blue);padding-top:22px}.finish label{display:flex;gap:12px;align-items:center;font-weight:600;font-size:16px}.finish input{width:20px;height:20px;accent-color:var(--blue)}.lesson-pagination{display:flex;gap:25px;justify-content:space-between;margin:25px 0;font-size:14px}.site-footer{font-size:12px;color:var(--muted);border-top:1px solid var(--line);padding-top:22px;margin-top:55px}#toast{position:fixed;bottom:20px;left:50%;background:#1c304f;color:#fff;padding:8px 22px;border-radius:5px;display:none;font-size:14px;z-index:20}#search-results{font-size:14px}#search-results a{display:block;padding:7px 5px;border-bottom:1px solid var(--line)}.skip{position:fixed;top:-70px;background:white;z-index:50;padding:8px}.skip:focus{top:0}.demo{border:1px solid #b9c9df;background:#eef3fa;padding:22px;margin:28px 0}.demo h3{margin:0 0 10px}.demo-label{font-size:13px;color:var(--muted);margin:0 0 18px}.demo label{display:block;font-size:15px;margin:12px 0}.demo input[type=range]{width:100%;accent-color:var(--blue)}.bars{display:flex;align-items:flex-end;gap:18px;height:160px;margin-top:24px;border-bottom:1px solid #8e9eb6}.bar-wrap{flex:1;text-align:center;font-size:14px}.bar{background:#38598e;min-height:4px;transition:height .2s}.bar-wrap span{display:block;font-variant-numeric:tabular-nums}.matrix{display:grid;gap:5px;grid-template-columns:repeat(4,1fr);margin:18px 0}.matrix span{padding:10px 5px;text-align:center;font-size:14px;background:#fff;border:1px solid #cad6e8}.matrix .blocked{background:#e1e4eb;color:#657187}.demo button{padding:6px 14px;background:#fff;color:var(--blue);border:1px solid #aabbd3;border-radius:3px}.demo input[type=text]{width:100%;padding:8px;border:1px solid #aabbd3}.demo-output{font-size:15px;overflow-wrap:anywhere}.hidden{display:none!important}@media(min-width:1600px){main{padding-left:100px;padding-right:100px}}@media(max-width:1100px){main{padding:35px 40px}.opening{grid-template-columns:1fr;gap:20px}.opening h1{font-size:50px}.book-note{padding:22px}.book-note ol{display:grid;grid-template-columns:1fr 1fr;font-size:20px;gap:4px 20px}.curriculum{grid-template-columns:1fr}}@media(max-width:760px){body{font-size:16px}.mobile-bar{display:flex;position:sticky;top:0;z-index:15;justify-content:space-between;align-items:center;background:#1c304f;color:white;padding:12px 18px}.mobile-bar a{color:white;text-decoration:none}.mobile-bar button{border:1px solid #a5b6ce;color:white;background:transparent;font-size:14px;border-radius:3px;padding:4px 10px}#sidebar{display:none;top:58px;z-index:12;width:min(320px,90vw);box-shadow:6px 0 25px #0002}#sidebar.open{display:block}main{margin-left:0;padding:26px 22px}h1{font-size:32px}h2{font-size:23px}.opening{margin-top:30px}.opening h1{font-size:44px}.book-note ol{display:block}.chapter-head{padding-top:23px}.breadcrumb{font-size:12px}.quickstart{padding:0 16px 15px}.lesson-pagination{flex-direction:column}.code-block{margin-left:-2px;margin-right:-2px}.demo{padding:17px}.table-scroll{max-width:calc(100vw - 44px)}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.bar{transition:none}}@media print{#sidebar,.mobile-bar,.copy,.finish,.site-footer{display:none}main{margin:0;padding:0;max-width:none}details{break-inside:avoid}.code-block{break-inside:avoid}pre{white-space:pre-wrap}body{font-size:12pt}}
.visual-nav{display:block;margin:0 0 24px;padding:13px 12px;background:#e3ebf6;border-left:3px solid var(--blue);text-decoration:none;font-weight:650;line-height:1.6}.visual-nav small{display:block;font-weight:400;color:var(--muted);font-size:12px;margin-top:3px}.illustrated-intro{margin:42px 0;padding:25px 28px;background:#edf2f8;border-top:3px solid var(--blue)}.illustrated-intro h2{margin-top:8px}.visual-toc{display:flex;flex-wrap:wrap;gap:9px;margin:28px 0}.visual-toc a{padding:7px 13px;border:1px solid #bdcbe0;background:white;border-radius:3px;text-decoration:none;font-size:14px}.course-figure{margin:32px 0 42px;border:1px solid #c9d4e1;border-radius:6px;background:white;overflow:hidden;scroll-margin-top:80px}.figure-label{display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap;padding:11px 18px;font-size:12px;color:var(--muted);background:#f1f5fa;border-bottom:1px solid var(--line)}.figure-label span:first-child{font-weight:650;color:var(--blue)}.figure-image{display:block;line-height:0;background:#eef2f7;cursor:zoom-in}.figure-image img{display:block;width:100%;height:auto;max-width:100%;border-bottom:1px solid var(--line)}.course-figure figcaption{padding:5px 22px 20px}.course-figure h3{margin:18px 0;font-size:20px}.course-figure dl{display:grid;grid-template-columns:100px minmax(0,1fr);gap:12px 13px;font-size:15px;line-height:1.8}.course-figure dt{font-weight:650;color:var(--blue)}.course-figure dd{margin:0;overflow-wrap:anywhere}.figure-actions{font-size:13px;margin:20px 0 10px}.figure-source{font-size:12px;color:var(--muted)}.figure-source summary{font-weight:400;font-size:12px}.figure-source p{overflow-wrap:anywhere;margin:8px 0 0}.stage-download{font-size:14px;padding:12px 15px;border-left:3px solid #8a9fbc;background:#f2f5f9}@media(max-width:760px){.course-figure figcaption{padding:4px 16px 17px}.course-figure dl{display:block}.course-figure dt{margin-top:15px}.course-figure dd{margin-top:4px}.figure-label{padding:9px 13px}.illustrated-intro{padding:20px}.visual-toc{gap:7px}.visual-toc a{font-size:13px}}@media print{.course-figure{break-inside:avoid}.figure-image img{max-height:190mm;object-fit:contain}.figure-actions{display:none}}
