:root{
  --paper:#f7f4ed;--paper-deep:#ece6d9;--white:#fffefd;--ink:#201c18;--muted:#696159;
  --line:#d8d0c2;--purple:#6d28d9;--purple-dark:#4c1d95;--purple-wash:#f1eafe;
  --teal:#0f766e;--teal-wash:#e4f5f1;--red:#b42318;--red-wash:#fff0ee;
  --amber:#9a5a08;--amber-wash:#fff4d5;--display:'DM Serif Display','Noto Sans SC',serif;
  --body:'Source Sans 3','Noto Sans SC',sans-serif;--mono:'JetBrains Mono',monospace;
  --shadow:0 18px 48px rgba(63,48,27,.09)
}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;min-height:100vh;background:var(--paper);color:var(--ink);font-family:var(--body);font-size:16px;line-height:1.65}body::before{content:"";position:fixed;inset:0;pointer-events:none;opacity:.36;background-image:linear-gradient(rgba(82,67,45,.035) 1px,transparent 1px);background-size:100% 28px}a{color:inherit}button,input,select,textarea{font:inherit}.topbar{position:relative;z-index:1;min-height:66px;padding:10px 28px;display:flex;align-items:center;justify-content:space-between;gap:18px;background:var(--paper);border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:12px;text-decoration:none}.brand-mark{width:40px;height:40px;border-radius:12px;display:grid;place-items:center;background:var(--ink);color:#fff;font-family:var(--display);font-size:19px;box-shadow:5px 5px 0 var(--purple)}.brand-copy strong{display:block;font-family:var(--display);font-size:19px;font-weight:400;line-height:1.05}.brand-copy span{display:block;margin-top:4px;color:var(--muted);font:700 10px/1 var(--mono);letter-spacing:.12em;text-transform:uppercase}.toplinks{display:flex;align-items:center;gap:7px;flex-wrap:wrap;justify-content:flex-end}.toplink{padding:7px 11px;border:1px solid var(--line);border-radius:999px;background:var(--white);color:var(--muted);text-decoration:none;font-size:12.5px;font-weight:800}.toplink:hover,.toplink.active{border-color:#bba8de;color:var(--purple-dark);background:var(--purple-wash)}.shell{position:relative;z-index:1;max-width:1180px;margin:0 auto;padding:42px 28px 86px}.hero{position:relative;overflow:hidden;padding:36px;border:1px solid var(--line);border-radius:24px;background:var(--white);box-shadow:0 2px 0 rgba(72,59,42,.04);margin-bottom:20px}.hero::after{content:attr(data-mark);position:absolute;right:30px;bottom:-55px;color:var(--purple-wash);font-family:var(--display);font-size:210px;line-height:1;transform:rotate(8deg);pointer-events:none}.kicker,.eyebrow{position:relative;z-index:1;color:var(--purple);font:800 11px/1.3 var(--mono);letter-spacing:.14em;text-transform:uppercase}.hero h1{position:relative;z-index:1;margin:12px 0 14px;max-width:800px;font:400 clamp(40px,6vw,68px)/.98 var(--display);letter-spacing:-.035em}.hero p{position:relative;z-index:1;max-width:760px;margin:0;color:var(--muted);font-size:16.5px}.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.grid.three{grid-template-columns:repeat(3,minmax(0,1fr))}.card{border:1px solid var(--line);border-radius:18px;background:var(--white);padding:24px;box-shadow:0 2px 0 rgba(72,59,42,.04)}.card.dark{background:var(--ink);color:#fff}.card h2,.card h3{font-family:var(--display);font-weight:400;line-height:1.12}.card h2{margin:8px 0 14px;font-size:30px}.card h3{margin:0 0 10px;font-size:23px}.card p{color:var(--muted)}.card.dark p{color:#cdc6bc}.toolbar{display:flex;align-items:end;gap:12px;flex-wrap:wrap;margin-bottom:16px}.field{flex:1;min-width:180px}.field label{display:block;margin-bottom:6px;color:var(--muted);font:800 11px var(--mono);letter-spacing:.06em;text-transform:uppercase}.input,.select,.textarea{width:100%;border:1px solid var(--line);border-radius:10px;background:var(--paper);color:var(--ink);padding:11px 13px}.textarea{min-height:110px;resize:vertical}.btn{min-height:43px;padding:0 16px;border:1px solid var(--line);border-radius:10px;background:var(--white);color:var(--ink);font-weight:800;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center}.btn:hover{border-color:#bba8de;background:var(--purple-wash)}.btn.primary{border-color:var(--purple);background:var(--purple);color:#fff;box-shadow:4px 4px 0 var(--purple-dark)}.btn.teal{border-color:var(--teal);background:var(--teal);color:#fff}.pill{display:inline-flex;padding:4px 9px;border-radius:999px;background:var(--purple-wash);color:var(--purple-dark);font:800 11px var(--mono)}.notice{padding:14px 16px;border-left:3px solid var(--teal);border-radius:9px;background:var(--teal-wash);color:#385e58;font-size:14px}.section-title{display:flex;align-items:end;justify-content:space-between;gap:18px;margin:32px 0 13px}.section-title h2{margin:0;font:400 32px/1 var(--display)}.section-title p{margin:0;color:var(--muted);font-size:13px}.footer{margin-top:34px;padding-top:18px;border-top:1px solid var(--line);display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;color:var(--muted);font-size:12.5px}.footer a{color:var(--purple-dark);font-weight:800}.math-line{overflow-x:auto}.source-note{margin-top:13px;padding-top:10px;border-top:1px dashed var(--line);color:var(--muted);font-size:12px}.empty{padding:34px;text-align:center;color:var(--muted)}
.katex-display{max-width:100%;overflow-x:auto;overflow-y:hidden}.bc-math-source{display:inline-block;max-width:100%;overflow-wrap:anywhere}
@media(max-width:920px){.grid,.grid.three{grid-template-columns:1fr}.topbar{align-items:flex-start}.shell{padding-top:28px}}
@media(max-width:640px){.topbar{padding:10px 14px}.brand-copy span{display:none}.toplinks{gap:5px}.toplink{padding:6px 8px;font-size:11.5px}.shell{padding:22px 14px 66px}.hero{padding:28px 22px}.hero h1{font-size:42px}.card{padding:20px}.section-title{align-items:flex-start;flex-direction:column}.toolbar{align-items:stretch;flex-direction:column}.field{width:100%}.btn{width:100%}}