:root{--ink-900:#0b1326;--ink-800:#16213a;--ink-700:#1f2a4a;--ink:#16213a;--ink-2:#3a4566;--mut:#5b6478;--mut-2:#8a93a8;--paper:#fbf6e8;--paper-2:#f4ecd6;--paper-3:#ece1c2;--line:#d8caa3;--card:#fffdf3;--copper:#b86b1f;--copper-2:#d18a3a;--copper-soft:#f0d9b2;--brass:#c89b3c;--brass-2:#8a6a23;--teal:#0e7c7b;--teal-2:#15a39e;--teal-soft:#ccebe9;--red:#9a3412;--red-2:#c2410c;--red-bg:#fff1e6;--red-line:#f6c79f;--ok:#15803d;--ok-bg:#eaf5ec;--warn:#b45309;--shadow-sm:0 1px 0 rgba(11,19,38,.04), 0 1px 2px rgba(11,19,38,.06);--shadow:0 1px 0 rgba(11,19,38,.04), 0 8px 24px rgba(11,19,38,.08);--shadow-lg:0 1px 0 rgba(11,19,38,.04), 0 24px 60px rgba(11,19,38,.1);--font-display:"Newsreader",Georgia,"Times New Roman",serif;--font-body:"Inter",system-ui,-apple-system,"Segoe UI",Arial,sans-serif;--font-mono:"JetBrains Mono",Consolas,"Courier New",monospace}*{box-sizing:border-box}html{font-size:17px;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;scroll-behavior:smooth}html,body{margin:0;padding:0}body{font-family:var(--font-body);background:var(--paper);color:var(--ink);line-height:1.75}body:before{content:"";position:fixed;inset:0;pointer-events:none;z-index:0;background-image:radial-gradient(rgba(11,19,38,.055) 1px,transparent 1px),radial-gradient(rgba(184,107,31,.035) 1px,transparent 1px);background-size:22px 22px,22px 22px;background-position:0 0,11px 11px}body>*{position:relative;z-index:1}a{color:#0e3b6b;text-decoration:none}a:hover{text-decoration:underline;text-underline-offset:3px}:focus-visible{outline:3px solid var(--teal-2);outline-offset:3px;border-radius:6px}@media(prefers-reduced-motion:reduce){*{animation-duration:.01ms!important;transition-duration:.01ms!important}}.topbar{background:linear-gradient(180deg,#fffdf3eb,#f4ecd6eb);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:50;backdrop-filter:saturate(180%) blur(10px);-webkit-backdrop-filter:saturate(180%) blur(10px)}.topbar:after{content:"";position:absolute;left:0;right:0;bottom:0;height:2px;background:linear-gradient(90deg,var(--copper),var(--brass),var(--teal-2),var(--brass),var(--copper))}.topbar-in{max-width:1240px;margin:0 auto;padding:12px 22px;display:flex;align-items:center;gap:14px;flex-wrap:wrap}.brand{font-family:var(--font-display);font-weight:700;font-size:21px;color:var(--ink-900);display:flex;align-items:center;gap:10px;letter-spacing:-.01em}.brand .pin{width:14px;height:14px;border-radius:50%;background:radial-gradient(circle at 30% 30%,#ffd27a,var(--brass) 55%,var(--brass-2));box-shadow:0 0 0 3px #c89b3c38,inset 0 1px #fff6;position:relative}.brand .pin:after{content:"";position:absolute;inset:0;border-radius:50%;box-shadow:0 0 14px var(--teal-2);opacity:.55;animation:ping 2.4s ease-out infinite}@keyframes ping{0%{transform:scale(1);opacity:.55}80%{transform:scale(1.6);opacity:0}to{opacity:0}}.crumb{font-size:13.5px;color:var(--mut)}.topbar nav{display:flex;gap:2px;flex-wrap:wrap;margin-left:auto;align-items:center}.topbar nav a{font-size:13.5px;font-weight:500;color:var(--ink-2);padding:7px 11px;border-radius:8px;position:relative;transition:background .15s,color .15s}.topbar nav a:hover{background:#0b13260f;text-decoration:none}.topbar nav a.cur{color:var(--teal);background:var(--teal-soft);font-weight:600}.topbar nav a.cur:after{content:"";position:absolute;left:11px;right:11px;bottom:2px;height:2px;background:var(--teal-2);border-radius:2px;box-shadow:0 0 8px var(--teal-2)}.hero{max-width:1240px;margin:30px auto 26px;padding:0 22px}.hero-card{position:relative;background:radial-gradient(1200px 280px at 12% 0%,rgba(21,163,158,.18),transparent 60%),radial-gradient(800px 260px at 92% 100%,rgba(200,155,60,.18),transparent 55%),linear-gradient(180deg,#0b1326,#16213a 60%,#1f2a4a);color:#f4ecd6;border-radius:18px;padding:36px 38px 40px;overflow:hidden;box-shadow:var(--shadow-lg);border:1px solid #2a3450}.hero-card:before{content:"";position:absolute;inset:0;background-image:linear-gradient(rgba(244,236,214,.04) 1px,transparent 1px),linear-gradient(90deg,rgba(244,236,214,.04) 1px,transparent 1px);background-size:34px 34px;mask-image:linear-gradient(180deg,#000 0,#000 60%,transparent 100%);-webkit-mask-image:linear-gradient(180deg,#000 0,#000 60%,transparent 100%);pointer-events:none}.hero-card .kicker{display:inline-flex;align-items:center;gap:10px;font-size:11.5px;letter-spacing:.22em;text-transform:uppercase;color:#d8caa3}.hero-card .kicker:before{content:"";width:24px;height:2px;background:var(--brass)}.hero-card h1{font-family:var(--font-display);font-weight:700;font-size:clamp(30px,4.2vw,46px);line-height:1.08;letter-spacing:-.02em;margin:14px 0 10px;color:#fbf6e8;max-width:780px}.hero-card h1 em{font-style:italic;color:#ffd27a}.hero-card p.lede{max-width:680px;color:#d8caa3;font-size:15.5px;margin:0 0 18px}.hero-dials{display:flex;flex-wrap:wrap;gap:8px;margin-top:14px;position:relative}.hero-dial{display:inline-flex;align-items:baseline;gap:8px;background:#fffdf30f;border:1px solid rgba(244,236,214,.18);border-radius:10px;padding:8px 14px;color:#fbf6e8;font-family:var(--font-display)}.hero-dial b{font-size:22px;font-weight:700;color:#ffd27a;font-variant-numeric:tabular-nums}.hero-dial span{font-size:11px;letter-spacing:.16em;text-transform:uppercase;color:#d8caa3}.hero-tag{position:absolute;right:20px;top:20px;background:var(--brass);color:#0b1326;font-size:11px;font-weight:700;letter-spacing:.18em;text-transform:uppercase;border-radius:999px;padding:6px 12px;box-shadow:0 4px 14px #00000040}.hero-cta{display:inline-flex;align-items:center;gap:10px;margin-top:22px;background:var(--teal-2);color:#062b2a;padding:11px 18px;border-radius:12px;font-weight:700;font-size:14px;letter-spacing:.04em;border:1px solid #0a5e5d;box-shadow:0 0 0 3px #0e7c7b2e,0 0 16px #15a39e59}.hero-cta:hover{background:#1cbcb5;text-decoration:none}.page{max-width:1240px;margin:0 auto;padding:8px 22px 80px;display:grid;grid-template-columns:280px 1fr;gap:32px;align-items:start}@media(max-width:1000px){.page{grid-template-columns:1fr;gap:18px}.side{position:static!important;max-height:none!important;overflow:visible!important}}.side{position:sticky;top:64px;align-self:start;max-height:calc(100vh - 80px);overflow:auto;padding:6px 4px 6px 0}.side::-webkit-scrollbar{width:8px}.side::-webkit-scrollbar-thumb{background:var(--line);border-radius:4px}.sg{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:8px 6px;margin-bottom:10px;box-shadow:var(--shadow-sm);position:relative}.sg:before{content:"";position:absolute;left:0;top:10px;bottom:10px;width:3px;border-radius:2px;background:var(--copper-soft)}.sg-title{font-size:10.5px;font-weight:700;color:var(--mut);text-transform:uppercase;letter-spacing:.12em;display:flex;justify-content:space-between;align-items:center;padding:4px 12px 6px;border-bottom:1px dashed var(--paper-3);margin-bottom:2px}.sg-title small{font-family:var(--font-mono);font-size:10.5px;color:var(--teal);background:var(--teal-soft);border-radius:6px;padding:1px 8px;letter-spacing:0;font-weight:700}.sg a{display:flex;align-items:center;gap:8px;padding:7px 12px;border-radius:8px;font-size:14px;font-weight:500;color:var(--ink-2);line-height:1.3;position:relative;transition:background .12s,color .12s}.sg a:hover{background:#0e7c7b0f;text-decoration:none;color:var(--teal)}.sg a.cur{background:linear-gradient(90deg,#0e7c7b29,#0e7c7b0f);color:#064f4e;font-weight:600}.sg a.cur:before{content:"";position:absolute;left:0;top:6px;bottom:6px;width:3px;background:var(--teal-2);border-radius:2px;box-shadow:0 0 8px var(--teal-2)}.sg a span.lbl{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}main{min-width:0}.h1{font-family:var(--font-display);font-weight:700;font-size:clamp(28px,3.6vw,40px);line-height:1.12;letter-spacing:-.015em;color:var(--ink-900);margin:6px 0 4px}.lede{font-size:16px;color:var(--ink-2);margin:0 0 18px;max-width:64ch}.statbar{display:flex;flex-wrap:wrap;gap:8px;margin:14px 0 6px}.chip{display:inline-flex;align-items:center;gap:6px;font-size:12.5px;font-weight:600;color:var(--ink-2);background:var(--card);border:1px solid var(--line);border-radius:999px;padding:5px 12px;box-shadow:var(--shadow-sm)}.chip b{font-family:var(--font-display);font-weight:700;color:var(--teal);font-size:14px}.tocrow{display:none}article{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:36px clamp(22px,3.4vw,52px) 40px;box-shadow:var(--shadow);position:relative}article:before{content:"";position:absolute;left:0;top:18px;bottom:18px;width:2px;background:linear-gradient(180deg,transparent,var(--copper) 12%,var(--brass) 50%,var(--copper) 88%,transparent);border-radius:2px}article h2{font-family:var(--font-display);font-size:26px;font-weight:700;letter-spacing:-.012em;color:var(--ink-900);margin:36px 0 6px;padding-top:18px;border-top:1px solid var(--paper-3)}article h2:first-of-type{margin-top:8px;padding-top:0;border-top:0}article h2:before{content:"§";font-style:italic;color:var(--copper);margin-right:10px;font-weight:600}article h3{font-family:var(--font-display);font-size:20px;font-weight:700;color:var(--ink-800);margin:22px 0 6px}article p{margin:10px 0;font-size:16.5px;line-height:1.8;color:var(--ink-2)}article strong{color:var(--ink-900);font-weight:700}article ul,article ol{margin:10px 0 10px 22px;font-size:16.5px;line-height:1.8;color:var(--ink-2)}article li{margin:4px 0}article li::marker{color:var(--copper);font-weight:700}article hr{border:0;border-top:1px dashed var(--paper-3);margin:32px 0}article blockquote{margin:16px 0;padding:14px 18px;background:var(--paper-2);border-left:4px solid var(--brass);border-radius:0 10px 10px 0;font-size:15.5px;color:var(--ink-2)}article blockquote p{margin:6px 0;font-size:15.5px}article table{width:100%;border-collapse:collapse;margin:14px 0;font-size:15px;background:var(--card)}article th,article td{padding:10px 12px;text-align:left;border-bottom:1px solid var(--paper-3);vertical-align:top}article th{font-family:var(--font-display);font-weight:700;color:var(--ink-900);background:var(--paper-2);font-size:14.5px}article tr:last-child td{border-bottom:0}article a{font-weight:600}.formula{background:linear-gradient(90deg,#fffefb,#fdf6df);border:1px solid var(--copper-soft);border-left:5px solid var(--copper);border-radius:10px;padding:14px 18px;margin:16px 0;font-size:16.5px;color:var(--ink);box-shadow:var(--shadow-sm);overflow-x:auto}.formula b{color:var(--brass-2);font-family:var(--font-mono);font-size:13px;letter-spacing:.06em;text-transform:uppercase}.callout{background:linear-gradient(180deg,#fff8eb,#fff3d6);border:1px solid var(--red-line);border-left:5px solid var(--warn);border-radius:10px;padding:14px 18px;margin:18px 0;font-size:15.5px;color:var(--ink-2)}.callout b{color:var(--warn)}.fig{text-align:center;margin:20px 0 10px}.fig img{max-width:100%;border:1px solid var(--line);border-radius:10px;background:#fff;box-shadow:var(--shadow-sm);padding:6px}.fig .cap{font-size:13px;color:var(--mut);margin-top:6px;line-height:1.6}.ref{font-size:13px!important;color:var(--mut)!important;border-top:1px dashed var(--paper-3);margin-top:28px!important;padding-top:14px}.ref b{color:var(--brass-2)}.v{font-family:var(--font-display);font-style:italic;font-weight:700;color:var(--ink-900)}.pyq{background:linear-gradient(180deg,#fffefb,#fdf8e8);border:1px solid var(--line);border-left:5px solid var(--red-2);border-radius:14px;padding:20px 24px 18px;margin:26px 0;box-shadow:var(--shadow);position:relative}.pyq:before{content:"QUESTION";position:absolute;right:14px;top:-11px;font-family:var(--font-mono);font-size:10px;font-weight:700;letter-spacing:.22em;color:#fff;background:var(--red-2);border-radius:5px;padding:3px 10px;box-shadow:0 2px 6px #c2410c59}.pyq .qno{font-family:var(--font-mono);font-size:13px;font-weight:700;color:#fff;background:var(--ink-900);border-radius:6px;padding:3px 11px;display:inline-block;margin-right:8px;letter-spacing:.04em}.pyq .qtext{display:inline;font-size:17px;font-weight:600;color:var(--ink-900);line-height:1.55;margin:0}.pyq p.qtext{display:block;margin:10px 0 8px}.pyq .yr{font-family:var(--font-mono);font-size:11.5px;font-weight:700;color:var(--red);background:var(--red-bg);border:1px solid var(--red-line);border-radius:6px;padding:2px 9px;display:inline-block;margin-right:4px;margin-bottom:6px;letter-spacing:.04em}.pyq .rep{font-family:var(--font-mono);font-size:11.5px;font-weight:700;color:#fff;background:var(--teal);border-radius:6px;padding:2px 9px;display:inline-block;margin-right:4px;margin-bottom:6px;letter-spacing:.04em}.pyq .rep.hot{background:var(--red-2);box-shadow:0 0 0 3px #c2410c2e}.pyq .lbl{display:flex;align-items:center;gap:8px;font-size:10.5px;font-weight:800;letter-spacing:.2em;text-transform:uppercase;margin:16px 0 5px;color:var(--brass-2)}.pyq .lbl:before{content:"";width:16px;height:2px;border-radius:1px;background:currentColor}.pyq span.lbl{display:flex}.pyq .recall{background:#b86b1f0f;border:1px dashed var(--copper-2);border-radius:9px;padding:11px 15px;margin:4px 0 10px;color:var(--ink-2);font-size:15.5px}.pyq .recall b{color:var(--brass-2)}.pyq ol.steps{counter-reset:step;list-style:none;padding:0;margin:8px 0 6px}.pyq ol.steps li{counter-increment:step;position:relative;padding:9px 0 9px 44px;margin:0;font-size:16px;line-height:1.75;border-bottom:1px dotted var(--paper-3);color:var(--ink-2)}.pyq ol.steps li:last-child{border-bottom:0}.pyq ol.steps li:before{content:counter(step);position:absolute;left:0;top:9px;width:28px;height:28px;border-radius:50%;background:var(--teal);color:#fff;font-family:var(--font-mono);font-weight:700;font-size:13px;display:flex;align-items:center;justify-content:center;box-shadow:0 0 0 3px var(--teal-soft)}.pyq .ans{background:linear-gradient(90deg,#fffefb,#fff3cf);border:2px solid var(--brass);border-radius:12px;padding:16px 18px;margin:10px 0 8px;font-size:17.5px;font-weight:600;color:var(--ink-900);position:relative;box-shadow:0 4px 14px #c89b3c2e}.pyq .ans:before{content:"ANSWER";position:absolute;right:12px;top:-11px;font-family:var(--font-mono);font-size:10px;font-weight:700;letter-spacing:.22em;color:#fff;background:var(--brass-2);border-radius:5px;padding:3px 10px}.pyq .ans b{color:var(--brass-2)}.pyq .ans .katex{color:var(--ink-900)}.pyq .tip{font-size:14.5px;color:#14532d;background:var(--ok-bg);border:1px solid #bfe0c6;border-left:4px solid var(--ok);border-radius:9px;padding:10px 14px;margin-top:10px}.pyq .tip:before{content:"EXAM TIP";font-family:var(--font-mono);font-size:9.5px;font-weight:700;letter-spacing:.2em;color:var(--ok);margin-right:8px}.pyq .fig{text-align:center;margin:14px 0 6px}.pyq .fig img{max-width:100%;border:1px solid var(--line);border-radius:8px;background:#fff}.pyq .fig .cap{font-size:13px;color:var(--mut);margin-top:4px}.footer{margin-top:22px;font-size:13px;color:var(--mut);display:flex;gap:8px;align-items:center}.footer a{color:var(--teal);font-weight:600}.katex-display{overflow-x:auto;overflow-y:hidden;padding:6px 0}.menubtn,.sidebtn{display:none}@media(max-width:900px){html{font-size:16px}.topbar-in{padding:10px 14px;gap:8px}.crumb{display:none}.menubtn{display:inline-flex;flex-direction:column;justify-content:center;gap:4px;width:42px;height:38px;margin-left:auto;background:var(--card);border:1px solid var(--line);border-radius:10px;cursor:pointer;padding:9px 11px}.menubtn span{display:block;height:2.5px;width:100%;border-radius:2px;background:var(--ink-800);transition:transform .18s,opacity .18s}.menubtn.open span:nth-child(1){transform:translateY(6.5px) rotate(45deg)}.menubtn.open span:nth-child(2){opacity:0}.menubtn.open span:nth-child(3){transform:translateY(-6.5px) rotate(-45deg)}.topbar nav{display:none;width:100%;flex-direction:column;align-items:stretch;gap:2px;margin:8px 0 4px;padding:8px 0 4px;border-top:1px dashed var(--line)}.topbar nav.open{display:flex}.topbar nav a{padding:10px 12px;font-size:15px;border-radius:8px}.topbar nav a.cur:after{left:12px;right:auto;width:26px}.hero{margin:16px auto 18px;padding:0 14px}.hero-card{padding:24px 20px 28px;border-radius:14px}.hero-tag{position:static;display:inline-block;margin-bottom:10px}.hero-card p.lede{font-size:14.5px}.hero-dial b{font-size:19px}.page{padding:8px 14px 60px;gap:14px}.sidebtn{display:block;width:100%;background:var(--card);border:1px solid var(--line);border-radius:12px;padding:12px 16px;font-family:var(--font-body);font-size:15px;font-weight:600;color:var(--ink-800);cursor:pointer;box-shadow:var(--shadow-sm)}.side{display:none;position:static;max-height:none;overflow:visible;padding:0;margin-top:8px}.side.open{display:block}main{width:100%}.h1{font-size:26px}.lede{font-size:15px}.statbar{gap:6px}.chip{font-size:12px;padding:4px 10px}article{padding:24px 16px 28px;border-radius:12px}article h2{font-size:21px;margin:28px 0 6px;padding-top:14px}article h3{font-size:18px}article p,article ul,article ol{font-size:15.5px}article ul,article ol{margin-left:20px}article table{display:block;overflow-x:auto;max-width:100%;-webkit-overflow-scrolling:touch;white-space:nowrap}article th,article td{min-width:120px;padding:8px 10px;font-size:14px}article blockquote{padding:12px 14px}.formula{padding:12px 14px;font-size:15px;border-radius:9px}.callout{padding:12px 14px;font-size:14.5px}.fig{margin:16px 0 8px}.fig img{padding:4px;border-radius:8px}.fig .cap{font-size:12.5px}.pyq{padding:16px 14px 14px;margin:24px 0 18px;border-radius:12px}.pyq:before{right:10px;font-size:9px;letter-spacing:.16em;padding:2px 8px}.pyq .qno{font-size:12px;padding:2px 9px}.pyq .qtext,.pyq p.qtext{font-size:16px}.pyq .recall{padding:10px 12px;font-size:14.5px}.pyq ol.steps li{padding:8px 0 8px 38px;font-size:15px}.pyq ol.steps li:before{width:26px;height:26px;font-size:12px;top:9px}.pyq .ans{padding:14px;font-size:16px;border-radius:10px}.pyq .ans:before{font-size:9px;letter-spacing:.16em;padding:2px 8px}.pyq .tip{font-size:13.5px;padding:9px 12px}.footer{flex-wrap:wrap;font-size:12.5px}}