:root{--bg:#f7f8fb;--surface:#fff;--surface2:#eef2f7;--text:#172033;--muted:#667085;--line:#dfe5ed;--brand:#5b47e8;--accent:#12a594;--code:#111827;--codeText:#e5e7eb;--shadow:0 16px 46px #1c243a1a;font-family:Inter,"Segoe UI","PingFang SC","Microsoft YaHei",system-ui,sans-serif;color-scheme:light}[data-theme=dark]{--bg:#0d1119;--surface:#151b26;--surface2:#202838;--text:#e8ecf4;--muted:#9aa5b8;--line:#2b3547;--brand:#9b8cff;--accent:#48d5bd;--code:#080b11;--codeText:#e5e7eb;--shadow:0 16px 46px #00000047;color-scheme:dark}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);line-height:1.72}a{color:var(--brand);text-decoration:none}a:hover{text-decoration:underline}button,input{font:inherit}.skip-link{position:fixed;top:-60px;left:12px;z-index:99;background:var(--surface);padding:9px 14px}.skip-link:focus{top:10px}.topbar{height:64px;position:fixed;z-index:30;inset:0 0 auto;display:flex;align-items:center;gap:18px;padding:0 24px;background:color-mix(in srgb,var(--surface) 90%,transparent);border-bottom:1px solid var(--line);backdrop-filter:blur(14px)}.brand{display:flex;align-items:center;gap:10px;font-weight:800;color:var(--text)}.brand:hover{text-decoration:none}.brand-mark{display:grid;place-items:center;width:34px;height:34px;border-radius:10px;color:#fff;background:linear-gradient(135deg,var(--brand),var(--accent));font-size:13px}.top-actions{display:flex;align-items:center;gap:10px;margin-left:auto}.icon-button,.search-button{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:9px;cursor:pointer}.icon-button{width:38px;height:38px}.search-button{display:flex;align-items:center;gap:9px;padding:7px 9px 7px 12px;color:var(--muted)}kbd{border:1px solid var(--line);border-radius:5px;padding:0 6px;background:var(--surface2);font-size:12px}.github-link{color:var(--text);font-weight:650}.menu-button,.sidebar-close{display:none}.layout{display:grid;grid-template-columns:280px minmax(0,1fr) 230px;max-width:1680px;margin:64px auto 0;min-height:calc(100vh - 64px)}.sidebar{position:sticky;top:64px;height:calc(100vh - 64px);overflow:auto;padding:22px 18px 60px;border-right:1px solid var(--line);background:var(--surface)}.sidebar-head{display:flex;align-items:center;justify-content:space-between;margin:0 7px 18px}.nav-group{margin-bottom:22px}.nav-group h2{margin:0 8px 6px;font-size:12px;color:var(--muted);letter-spacing:.08em}.nav-group a{display:flex;gap:7px;padding:7px 9px;border-radius:8px;color:var(--muted);font-size:13px;line-height:1.42}.nav-group a:hover{background:var(--surface2);color:var(--text);text-decoration:none}.nav-group a[aria-current=page]{background:color-mix(in srgb,var(--brand) 12%,var(--surface));color:var(--brand);font-weight:700}.kind{font-size:9px;border:1px solid;border-radius:4px;padding:0 3px;height:17px}.main{min-width:0;padding:54px clamp(28px,5vw,82px) 100px}.article{max-width:900px;margin:auto}.article-kicker,.eyebrow{font-size:12px;font-weight:800;text-transform:uppercase;letter-spacing:.11em;color:var(--brand)}.article-body h1{font-size:clamp(32px,5vw,49px);line-height:1.12;letter-spacing:-.035em;margin:14px 0 30px}.article-body h2{font-size:28px;line-height:1.25;margin:58px 0 16px;padding-top:10px}.article-body h3{font-size:21px;margin:38px 0 12px}.anchor{opacity:0;margin-left:8px;font-size:.7em}.article-body h2:hover .anchor,.article-body h3:hover .anchor{opacity:.65}.article-body p,.article-body li{font-size:16px}.article-body img{display:block;max-width:100%;height:auto;margin:26px auto;border-radius:12px}.article-body table{display:block;width:100%;overflow:auto;border-collapse:collapse;margin:24px 0}.article-body th,.article-body td{border:1px solid var(--line);padding:10px 13px;text-align:left}.article-body th{background:var(--surface2)}blockquote{margin:25px 0;padding:8px 20px;border-left:4px solid var(--brand);background:var(--surface);color:var(--muted)}pre{overflow:auto;background:var(--code);color:var(--codeText);border-radius:12px;padding:18px 20px;line-height:1.55}code{font-family:"Cascadia Code",Consolas,monospace;font-size:.9em}.article-body :not(pre)>code{padding:2px 6px;border-radius:5px;background:var(--surface2);color:var(--brand)}.toc{position:sticky;top:64px;height:calc(100vh - 64px);padding:48px 22px;border-left:1px solid var(--line);overflow:auto}.toc strong{display:block;margin-bottom:12px;font-size:13px}.toc a{display:block;padding:5px 0;color:var(--muted);font-size:12px;line-height:1.45}.toc a.active{color:var(--brand);font-weight:700}.toc .toc-3{padding-left:13px}.toc-empty{font-size:12px;color:var(--muted)}.notice,.offline-note{border:1px solid color-mix(in srgb,var(--brand) 35%,var(--line));background:color-mix(in srgb,var(--brand) 7%,var(--surface));border-radius:13px;padding:17px 20px;margin:22px 0}.notice p,.offline-note p{margin:4px 0 0;color:var(--muted)}.nb-cell{margin:25px 0}.cell-label{font:12px "Cascadia Code",monospace;color:var(--muted);margin-bottom:5px}.cell-output{border-left:3px solid var(--line);padding-left:18px;margin:12px 0 32px}.output-text{background:var(--surface2);color:var(--text)}.output-image{max-width:100%}.output-html{overflow:auto}.article-footer{display:flex;flex-wrap:wrap;align-items:center;gap:12px;margin-top:70px;padding-top:25px;border-top:1px solid var(--line);color:var(--muted);font-size:13px}.button{display:inline-flex;padding:10px 16px;border-radius:9px;font-weight:750}.button:hover{text-decoration:none;transform:translateY(-1px)}.button.primary{background:var(--brand);color:#fff}.button.secondary{border:1px solid var(--line);background:var(--surface);color:var(--text)}.search-dialog{width:min(720px,calc(100vw - 28px));padding:0;border:1px solid var(--line);border-radius:16px;background:var(--surface);color:var(--text);box-shadow:var(--shadow)}.search-dialog::backdrop{background:#05091299;backdrop-filter:blur(3px)}.search-panel{max-height:80vh;display:flex;flex-direction:column}.search-head{display:flex;padding:13px;border-bottom:1px solid var(--line)}.search-head input{flex:1;border:0;outline:0;background:transparent;color:var(--text);padding:6px 10px;font-size:18px}.search-results{overflow:auto;padding:10px}.search-results>p{padding:20px;color:var(--muted)}.search-results a{display:block;padding:13px 15px;border-radius:10px;color:var(--text)}.search-results a:hover{background:var(--surface2);text-decoration:none}.search-results span{color:var(--brand);font-size:11px;font-weight:800}.search-results strong{display:block}.search-results p{margin:4px 0;color:var(--muted);font-size:12px}.home-main{max-width:1320px;margin:64px auto 0;padding:80px 34px}.hero{display:grid;grid-template-columns:1.05fr .95fr;align-items:center;gap:68px;min-height:600px}.hero h1{font-size:clamp(42px,5vw,70px);line-height:1.06;letter-spacing:-.05em;margin:18px 0 25px}.hero p{font-size:18px;color:var(--muted)}.hero-actions{display:flex;flex-wrap:wrap;gap:10px;margin:30px 0}.stats{display:flex;gap:28px;margin-top:40px;color:var(--muted);font-size:13px}.stats strong{display:block;font-size:23px;color:var(--text)}.hero-art img{width:100%;border-radius:22px;box-shadow:var(--shadow);background:#fff}.offline-note{max-width:950px;margin:20px auto 95px}.section-heading h2{font-size:35px;margin:5px 0 24px}.home-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:15px}.home-card{display:flex;flex-direction:column;min-height:175px;padding:22px;border:1px solid var(--line);border-radius:15px;background:var(--surface);color:var(--text)}.home-card:hover{border-color:var(--brand);transform:translateY(-2px);text-decoration:none}.home-card span{font-size:17px;font-weight:800}.home-card strong{margin-top:8px;color:var(--muted);font-size:13px}.home-card i{margin-top:auto;color:var(--brand);font-style:normal;font-weight:700}.home-footer{margin-top:90px;padding-top:25px;border-top:1px solid var(--line);color:var(--muted);font-size:13px}.sidebar-backdrop{display:none}
@media(max-width:1160px){.layout{grid-template-columns:260px minmax(0,1fr)}.toc{display:none}.home-grid{grid-template-columns:repeat(2,1fr)}}@media(max-width:820px){.topbar{padding:0 14px}.menu-button{display:block}.github-link,.search-button span,.search-button kbd{display:none}.search-button{width:38px;height:38px;padding:0;justify-content:center}.layout{display:block}.sidebar{position:fixed;z-index:50;top:0;left:0;width:min(310px,88vw);height:100vh;transform:translateX(-105%);transition:.2s;box-shadow:var(--shadow)}.sidebar-open .sidebar{transform:none}.sidebar-close{display:block}.sidebar-backdrop{position:fixed;z-index:45;inset:0;background:#0007}.sidebar-open .sidebar-backdrop{display:block}.main{padding:38px 20px 80px}.article-body h1{font-size:34px}.home-main{padding:55px 20px}.hero{grid-template-columns:1fr;gap:35px;min-height:auto}.hero h1{font-size:43px}.hero-art{order:-1}.home-grid{grid-template-columns:1fr}.stats{gap:18px;flex-wrap:wrap}}@media print{.topbar,.sidebar,.toc,.article-footer{display:none!important}.layout{display:block;margin:0}.main{padding:0}.article{max-width:none}body{background:#fff;color:#000}}
 .brand-logo{width:34px;height:34px;border-radius:10px;object-fit:cover;box-shadow:0 5px 14px #1c243a22}.site-link{color:var(--brand);font-weight:700}.breadcrumbs{display:flex;flex-wrap:wrap;gap:7px;align-items:center;margin-bottom:20px;color:var(--muted);font-size:12px}.breadcrumbs span{color:var(--muted)}.lesson-neighbors{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin-top:58px}.lesson-neighbor{display:flex;flex-direction:column;gap:2px;padding:14px 16px;border:1px solid var(--line);border-radius:11px;background:var(--surface);color:var(--text)}.lesson-neighbor.next{text-align:right}.lesson-neighbor small{color:var(--muted);font-size:11px}.lesson-neighbor strong{color:var(--brand);font-size:13px}.home-footer a{font-weight:700}@media(max-width:820px){.site-link{display:none}.lesson-neighbors{grid-template-columns:1fr}.lesson-neighbor.next{text-align:left}}
.home-ad{max-width:950px;min-height:120px;margin:36px auto 78px;padding:10px 0;text-align:center}.home-ad .adsbygoogle{min-height:90px}@media(max-width:820px){.home-ad{min-height:100px;margin:28px auto 60px;padding:6px 0}}