:root{--bg:#f7f8fb;--fg:#0f1b2d;--muted:#5b6678;--card:#fff;--line:#e6e9f0;--brand:#0b2a4a;--brand2:#0f766e;--acc:#ff7a1a;--link:#0b5ea8;--sh:0 1px 2px rgba(15,27,45,.05),0 6px 20px rgba(15,27,45,.06);--sh2:0 4px 10px rgba(15,27,45,.08),0 18px 40px rgba(15,27,45,.10);--r:14px}
[data-theme=dark]{--bg:#0b111b;--fg:#e7ecf4;--muted:#97a3b6;--card:#121a27;--line:#223047;--link:#7cc0ff;--sh:0 1px 2px #0006;--sh2:0 10px 30px #0008}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:72px}
body{margin:0;font:17px/1.7 ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--fg);background:var(--bg);-webkit-font-smoothing:antialiased}
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.w{max-width:1200px;margin:0 auto;padding:0 1.25rem}main.w{padding-top:1.5rem;padding-bottom:3rem}
.skip{position:absolute;left:-999px}.skip:focus{left:1rem;top:1rem;z-index:99;background:#fff;padding:.5rem}
#progress{position:fixed;top:0;left:0;height:3px;width:0;background:var(--acc);z-index:60}
header{position:sticky;top:0;z-index:50;background:rgba(11,42,74,.92);backdrop-filter:saturate(1.4) blur(10px);border-bottom:1px solid #ffffff14}
.hd{display:flex;align-items:center;gap:1rem;height:60px}
.brand{display:flex;align-items:center;gap:.55rem;color:#fff;font-weight:800;font-size:1.08rem;text-decoration:none;white-space:nowrap}.brand em{font-style:normal;color:#ffb27a;font-weight:600}
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.dd>button{display:flex;align-items:center;gap:.35rem;background:none;border:0;color:#d6e2f2;font:inherit;font-size:.92rem;font-weight:500;padding:.45rem .7rem;border-radius:8px;cursor:pointer}
.dd>button:hover,.dd.open>button{background:#ffffff18;color:#fff}
.mega{position:absolute;left:-.5rem;top:calc(100% + 8px);background:var(--card);border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--sh2);padding:.5rem;min-width:300px;opacity:0;visibility:hidden;transform:translateY(-4px);transition:.15s}
.dd:hover .mega,.dd.open .mega,.dd:focus-within .mega{opacity:1;visibility:visible;transform:none}
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.sbox{position:relative;margin-left:auto}.sbox input{width:240px;padding:.5rem .8rem;border-radius:10px;border:1px solid #ffffff2a;background:#ffffff14;color:#fff;font:inherit;font-size:.9rem}.sbox input::placeholder{color:#c7d3e4}.sbox input:focus{outline:2px solid var(--acc);background:#fff;color:#0f1b2d}
.sres{position:absolute;right:0;top:calc(100% + 8px);width:420px;max-width:92vw;background:var(--card);border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--sh2);display:none;max-height:70vh;overflow:auto}
.sres a,#results a{display:block;padding:.6rem .9rem;color:var(--fg);text-decoration:none;border-bottom:1px solid var(--line);font-size:.92rem}.sres a:hover,#results a:hover{background:color-mix(in srgb,var(--brand2) 8%,transparent)}.sres small,#results small{display:block;color:var(--muted);font-size:.8rem}
.theme{background:none;border:1px solid #ffffff33;color:#fff;border-radius:8px;width:34px;height:34px;cursor:pointer}
.burger{display:none;background:none;border:0;width:36px;height:36px;padding:8px;cursor:pointer}.burger span{display:block;height:2px;background:#fff;margin:4px 0;border-radius:2px}
.hero{position:relative;overflow:hidden;color:#fff;background:radial-gradient(1200px 500px at 85% -10%,#14b8a655,transparent 60%),radial-gradient(900px 400px at -10% 120%,#ff7a1a33,transparent 60%),linear-gradient(160deg,#0b2a4a,#0c3b5e 55%,#0f766e);padding:4.5rem 0 4rem}
.hero::after{content:"";position:absolute;inset:0;background-image:linear-gradient(#ffffff0d 1px,transparent 1px),linear-gradient(90deg,#ffffff0d 1px,transparent 1px);background-size:40px 40px;mask-image:linear-gradient(to bottom,#000,transparent);pointer-events:none}
.hero .w{position:relative;z-index:1}.eyebrow{display:inline-block;font-size:.8rem;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:#ffb27a;background:#ffffff12;padding:.25rem .7rem;border-radius:99px;margin:0}
.hero h1{font-size:clamp(2.2rem,5vw,3.6rem);font-weight:800;margin:1rem 0 .8rem}.hero .sub{font-size:1.15rem;color:#d3e0ef;max-width:680px}
.herosearch{display:flex;align-items:center;gap:.6rem;max-width:760px;margin-top:1.6rem;background:#fff;border-radius:16px;padding:.45rem .45rem .45rem 1rem;box-shadow:0 20px 50px #0006;color:#5b6678}
.herosearch input{flex:1;border:0;outline:0;font:inherit;font-size:1.1rem;padding:.7rem 0;color:#0f1b2d;background:none;min-width:0}
.herosearch button{background:var(--acc);color:#fff;border:0;border-radius:12px;padding:.85rem 1.4rem;font-weight:700;font-size:1rem;cursor:pointer}.herosearch button:hover{filter:brightness(1.05)}
.chips{display:flex;flex-wrap:wrap;gap:.5rem;margin-top:1.1rem}.chip{color:#e6eef8;text-decoration:none;font-size:.88rem;padding:.35rem .85rem;border:1px solid #ffffff33;border-radius:99px;background:#ffffff0f;transition:.15s}.chip:hover{background:#ffffff26;border-color:#ffffff66}
.hs{margin:3.2rem 0}.hs-h{display:flex;align-items:end;justify-content:space-between;gap:1rem;margin-bottom:1.1rem}.hs-h h2{margin:0}.hs-h p{margin:.3rem 0 0;color:var(--muted)}.more{font-weight:600;text-decoration:none;white-space:nowrap}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:1.1rem}.g3{grid-template-columns:repeat(auto-fill,minmax(300px,1fr))}.g4{grid-template-columns:repeat(auto-fill,minmax(240px,1fr))}
.card{display:block;position:relative;background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:1.2rem 1.25rem;box-shadow:var(--sh);transition:transform .18s,box-shadow .18s,border-color .18s;color:var(--fg)}
a.card{text-decoration:none}.card:hover{transform:translateY(-3px);box-shadow:var(--sh2);border-color:color-mix(in srgb,var(--brand2) 35%,var(--line))}
.card h3{margin:.5rem 0 .35rem}.card p{margin:.3rem 0;font-size:.93rem;color:var(--muted)}.card h3 a{text-decoration:none;color:var(--fg)}.card h3 a::after{content:"";position:absolute;inset:0}
.cnt{display:inline-block;margin-top:.5rem;font-size:.8rem;font-weight:600;color:var(--brand2)}
.ic{display:inline-grid;place-items:center;width:44px;height:44px;border-radius:12px;background:color-mix(in srgb,var(--brand2) 12%,transparent);color:var(--brand2)}
.card.mini h3{font-size:1rem}.lv{border-top:4px solid}.lvb0{border-top-color:#22a06b}.lvb1{border-top-color:#2f6fde}.lvb2{border-top-color:#ff7a1a}.lvb3{border-top-color:#8b5cf6}
.vid .play{display:inline-grid;place-items:center;width:36px;height:36px;border-radius:50%;background:var(--acc);color:#fff;margin-right:.4rem;vertical-align:middle}
.tag{display:inline-block;font-size:.74rem;font-weight:600;border-radius:99px;padding:.15rem .6rem;background:#e7eef8;color:#0b2a4a}.tag.soft{background:color-mix(in srgb,var(--muted) 14%,transparent);color:var(--muted)}
.lvl0{background:#dcf5e8;color:#0d6b41}.lvl1{background:#dde8fd;color:#1d4fb3}.lvl2{background:#ffe9d6;color:#a2480a}.lvl3{background:#ece3fe;color:#5b30c2}
.stub{font-size:.7rem;color:var(--muted);border:1px dashed var(--muted);border-radius:99px;padding:0 .45rem;margin-left:.3rem}
.lead{font-size:1.15rem;color:var(--muted);max-width:760px}.note{font-size:.85rem;color:var(--muted)}.crumbs{font-size:.85rem;color:var(--muted)}.crumbs a{color:var(--muted)}.meta{display:flex;flex-wrap:wrap;gap:.4rem}
.tiers{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:1rem}.tier{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:.4rem 1.2rem 1rem;box-shadow:var(--sh)}.tier ul{padding-left:1.1rem}.tier li{margin:.25rem 0}
.layout{display:grid;grid-template-columns:240px minmax(0,1fr);gap:3rem;align-items:start}
.toc{position:sticky;top:84px;max-height:calc(100vh - 100px);overflow:auto;font-size:.88rem;border-right:1px solid var(--line);padding-right:1rem}.toc-h{font-weight:700;font-size:.75rem;letter-spacing:.06em;text-transform:uppercase;color:var(--muted);margin:1rem 0 .4rem}
.toc ol{list-style:none;padding:0;margin:0}.toc a{display:block;padding:.28rem .6rem;border-radius:8px;color:var(--muted);text-decoration:none;border-left:2px solid transparent}.toc a:hover{color:var(--fg)}.toc a.on,.toc a[aria-current]{color:var(--brand2);background:color-mix(in srgb,var(--brand2) 9%,transparent);font-weight:600}
.topic{max-width:760px}.prose p{margin:0 0 1.1rem}
.call{border-radius:var(--r);padding:1rem 1.2rem;margin:1.4rem 0;border:1px solid;background:var(--card)}.call>b:first-child{display:flex;align-items:center;gap:.4rem;font-size:.82rem;text-transform:uppercase;letter-spacing:.06em}
.fx{border-color:#9ec5ff;background:color-mix(in srgb,#2f6fde 6%,var(--card))}.fx>b{color:#1d4fb3}.fx code{font:500 .93rem/1.6 ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}.fx ul{padding-left:1.1rem}
.ex{border-color:#ffc89e;background:color-mix(in srgb,#ff7a1a 6%,var(--card))}.ex>b{color:#a2480a}.ans{font-weight:600}
.tip{border-color:#9be3c4;background:color-mix(in srgb,#22a06b 7%,var(--card))}.tip>b{color:#0d6b41}
.warn{border-color:#f5b0b0;background:color-mix(in srgb,#e5484d 7%,var(--card))}.warn>b{color:#b42318}
.code{border-color:#cdb8ff;background:color-mix(in srgb,#8b5cf6 6%,var(--card))}.code>b{color:#5b30c2}
[data-theme=dark] .fx>b,[data-theme=dark] .ex>b,[data-theme=dark] .tip>b,[data-theme=dark] .warn>b,[data-theme=dark] .code>b{filter:brightness(1.8)}
.quiz{margin:2rem 0}.q{background:var(--card);border:1px solid var(--line);border-radius:12px;margin:.6rem 0;box-shadow:var(--sh)}.q summary{list-style:none;cursor:pointer;padding:.85rem 1rem;display:flex;gap:.7rem;align-items:center;font-weight:600}.q summary::-webkit-details-marker{display:none}
.qn{flex:none;display:grid;place-items:center;width:28px;height:28px;border-radius:50%;background:var(--brand);color:#fff;font-size:.82rem}.q[open] .qn{background:#22a06b}.q p{margin:0;padding:0 1rem 1rem 3.4rem;color:var(--muted)}.q summary::after{content:"Show answer";margin-left:auto;font-size:.78rem;color:var(--link);font-weight:500}.q[open] summary::after{content:"Hide"}
.dg{margin:1.5rem 0}.dg svg{width:100%;max-width:560px;background:color-mix(in srgb,var(--brand2) 6%,var(--card));border:1px solid var(--line);border-radius:var(--r);padding:.5rem}[data-theme=dark] .dg g{stroke:#cfe3ff}.dg figcaption{font-size:.78rem;color:var(--muted);margin-top:.3rem}
.tw{overflow-x:auto;border:1px solid var(--line);border-radius:var(--r);box-shadow:var(--sh)}table.codes{border-collapse:collapse;width:100%;font-size:.88rem;background:var(--card)}.codes th,.codes td{border-bottom:1px solid var(--line);padding:.6rem .75rem;text-align:left;vertical-align:top}.codes th{background:var(--brand);color:#fff;font-weight:600;position:sticky;top:0}.codes tr:hover td{background:color-mix(in srgb,var(--brand2) 5%,transparent)}.hist{color:#c2410c;font-weight:600}
.cols{columns:2 320px}.az{display:flex;flex-wrap:wrap;gap:.3rem}.az a{display:grid;place-items:center;width:34px;height:34px;border-radius:8px;background:var(--card);border:1px solid var(--line);text-decoration:none;font-weight:700}
dl{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:.5rem 1.2rem}dt{font-weight:700;margin-top:.8rem}dd{margin:0 0 .6rem;color:var(--muted)}
.refs{border-top:1px solid var(--line);margin-top:2.5rem}.filters{display:flex;gap:1rem;flex-wrap:wrap;margin:1rem 0}.filters select{padding:.45rem;border-radius:8px;border:1px solid var(--line);background:var(--card);color:var(--fg);font:inherit}
.calc{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:1.3rem;box-shadow:var(--sh)}.calc textarea,.calc input{font:inherit;padding:.55rem .7rem;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--fg)}.calc textarea{width:100%;font-family:ui-monospace,monospace}
.calc button{margin:.8rem 0;background:var(--acc);color:#fff;border:0;border-radius:10px;padding:.65rem 1.3rem;font-weight:700;cursor:pointer}
.form{display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:.8rem}.form label{display:flex;flex-direction:column;gap:.25rem;font-size:.86rem;color:var(--muted)}
p.warn{border:1px solid #f5d38a;background:#fff7e0;color:#6b4e00;padding:.6rem .9rem;border-radius:10px}
input.big{width:100%;padding:.9rem 1rem;font:inherit;font-size:1.15rem;border:1px solid var(--line);border-radius:14px;background:var(--card);color:var(--fg);box-shadow:var(--sh)}
footer{border-top:1px solid var(--line);background:var(--card);font-size:.88rem;color:var(--muted);padding:1.5rem 0}
:focus-visible{outline:2px solid var(--acc);outline-offset:2px}
@media(max-width:1000px){.layout{grid-template-columns:1fr}.toc{position:static;border:0;max-height:none;padding:0}.toc .sib,.toc .toc-h+ol.sib{display:none}}
@media(max-width:900px){.burger{display:block}.nav{position:fixed;inset:60px 0 0 0;background:var(--card);transform:translateX(-100%);transition:transform .2s;overflow:auto;padding:1rem}.nav.open{transform:none}
.menu{flex-direction:column}.dd>button{color:var(--fg);width:100%;justify-content:space-between;font-size:1.05rem;padding:.8rem}.mega{position:static;opacity:1;visibility:visible;transform:none;box-shadow:none;border:0;display:none;padding:0 0 .5rem .5rem}.dd.open .mega{display:block}
.sbox{flex:1;min-width:0}.sbox input{width:100%}.hero{padding:3rem 0}.herosearch button{padding:.8rem 1rem}.hs-h{flex-direction:column;align-items:start}}
@media(max-width:520px){.brand em{display:none}body{font-size:16px}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}
@media print{header,footer,.toc,.sbox,#progress{display:none}.layout{display:block}body{background:#fff;color:#000}}

.lim{border-color:#c9b6f2;background:color-mix(in srgb,#7c4ddb 6%,var(--card))}
.lim>b{color:#5b2fb0}
.lim ul{padding-left:1.1rem;margin:.4rem 0 0}
[data-theme=dark] .lim>b{filter:brightness(1.8)}