:root{--paper: #faf9f6;--card: #ffffff;--ink: #10202f;--ink-soft: #3d4f60;--muted: #6b7a89;--line: #e6e3dc;--line-soft: #efece6;--brand: #1b4f8f;--brand-ink: #0d2a4a;--brand-soft: #eaf1fa;--accent: #0f8f80;--accent-soft: #e6f5f2;--shadow: 0 1px 2px rgba(16, 32, 47, .04), 0 8px 24px rgba(16, 32, 47, .05);--radius: 14px;color-scheme:light}:root[data-theme=dark]{--paper: #0c1017;--card: #141a22;--ink: #e8eef5;--ink-soft: #c3ced9;--muted: #8c9aa8;--line: #232c37;--line-soft: #1b232c;--brand: #6ea8fe;--brand-ink: #cfe1ff;--brand-soft: #16233a;--accent: #3dd6c0;--accent-soft: #102b2a;--shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 10px 30px rgba(0, 0, 0, .35);color-scheme:dark}*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:84px}body{margin:0;background:var(--paper);color:var(--ink);font-family:-apple-system,BlinkMacSystemFont,PingFang SC,Hiragino Sans GB,Microsoft YaHei,Source Han Sans SC,Noto Sans CJK SC,sans-serif;font-size:16px;line-height:1.75;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}a{color:inherit;text-decoration:none}::selection{background:var(--brand-soft);color:var(--brand-ink)}.site-header{position:sticky;top:0;z-index:50;height:64px;display:flex;align-items:center;gap:20px;padding:0 24px;background:color-mix(in srgb,var(--paper) 82%,transparent);backdrop-filter:saturate(180%) blur(14px);-webkit-backdrop-filter:saturate(180%) blur(14px);border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:10px;font-weight:700;letter-spacing:.2px}.brand-mark{width:30px;height:30px;border-radius:9px;background:linear-gradient(140deg,var(--brand),var(--accent));color:#fff;display:grid;place-items:center;font-size:13px;font-weight:800;letter-spacing:-.4px}.brand small{display:block;font-size:11px;font-weight:500;color:var(--muted);letter-spacing:.4px}.nav{display:flex;align-items:center;gap:4px;margin-left:8px}.nav a{padding:7px 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h1{font-size:44px;line-height:1.22;letter-spacing:-.02em;margin:14px 0 18px;font-weight:800}.hero p.lead{font-size:17px;color:var(--ink-soft);max-width:40em;margin:0 0 28px}.hero-stats{display:flex;gap:30px;margin-top:34px;padding-top:26px;border-top:1px solid var(--line)}.hero-stats b{display:block;font-size:26px;font-weight:800;letter-spacing:-.02em}.hero-stats span{font-size:13px;color:var(--muted)}.hero-panel{padding:24px}.hero-panel h3{margin:0 0 14px;font-size:14px;letter-spacing:.04em;color:var(--muted);font-weight:600}.hero-panel ol{margin:0;padding:0;list-style:none;counter-reset:s}.hero-panel li{counter-increment:s;position:relative;padding:11px 0 11px 34px;border-bottom:1px dashed var(--line-soft);font-size:14.5px}.hero-panel li:last-child{border-bottom:0}.hero-panel li:before{content:counter(s,decimal-leading-zero);position:absolute;left:0;top:11px;font-size:12px;font-weight:700;color:var(--brand);background:var(--brand-soft);border-radius:6px;padding:1px 6px;font-variant-numeric:tabular-nums}.section{padding:64px 0}.section-head{display:flex;align-items:flex-end;justify-content:space-between;gap:24px;margin-bottom:30px}.section-head h2{font-size:27px;letter-spacing:-.01em;margin:8px 0 0;font-weight:750}.section-head p{margin:8px 0 0;color:var(--muted);font-size:14.5px}.part-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.part-card{padding:24px;display:flex;flex-direction:column;gap:12px}.part-card h3{margin:0;font-size:17px;font-weight:700}.part-card ul{margin:0;padding:0;list-style:none;display:flex;flex-direction:column;gap:7px}.part-card li a{font-size:14px;color:var(--ink-soft);display:flex;justify-content:space-between;gap:10px;padding:3px 0}.part-card li a:hover{color:var(--brand)}.part-card li span{color:var(--muted);font-size:12px;font-variant-numeric:tabular-nums;white-space:nowrap}.course-shell{display:grid;grid-template-columns:274px minmax(0,1fr);gap:0;max-width:1320px;margin:0 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.next{text-align:right}dialog.lightbox{border:0;padding:0;background:transparent;max-width:96vw;max-height:94vh}dialog.lightbox::backdrop{background:#080e16d1;backdrop-filter:blur(4px)}dialog.lightbox img{display:block;max-width:94vw;max-height:88vh;border-radius:10px;box-shadow:0 24px 70px #00000080;background:#fff}dialog.lightbox .lb-bar{display:flex;align-items:center;justify-content:space-between;gap:12px;padding:10px 4px 0;color:#d8e2ec;font-size:13px}dialog.lightbox button{background:#ffffff1f;color:#fff;border:0;border-radius:8px;padding:5px 12px;cursor:pointer;font-size:13px}.search-box{display:flex;align-items:center;gap:10px;padding:0 16px;height:54px;border:1px solid var(--line);border-radius:12px;background:var(--card)}.search-box input{flex:1;border:0;outline:0;background:transparent;color:var(--ink);font-size:16px;font-family:inherit}.hit{display:block;padding:18px 0;border-bottom:1px solid var(--line-soft)}.hit:hover h3{color:var(--brand)}.hit h3{margin:0 0 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