@font-face{font-family:Rungs Display;src:url(/Fraunces-var.woff2)format("woff2");font-weight:100 900;font-display:swap}.math-room{--math-paper:#fffbf0;--math-ground:#eaf6ff;--math-ink:#1e2a44;--math-muted:#526077;--math-pine:#28683b;--math-rule:#bcc8c9;--math-error:#9a3030;--math-gap:clamp(24px, 4vw, 64px);--math-display:"Rungs Display", Georgia, serif;background:var(--math-paper);color:var(--math-ink);padding:var(--math-gap);flex:1}.math-room *{box-sizing:border-box}.math-intro,.math-desk{max-width:1180px;margin:auto}.math-intro{padding-block:24px 48px}.math-kicker{font-family:var(--font-geist-mono), monospace;letter-spacing:.08em;color:var(--math-muted);font-size:12px}.math-intro h1{font-family:var(--math-display);letter-spacing:-.05em;margin:24px 0;font-size:clamp(56px,8vw,112px);font-weight:620;line-height:.95}.math-lead{max-width:42ch;font-size:clamp(19px,2vw,24px);line-height:1.5}.math-note{color:var(--math-muted);max-width:64ch;margin-block:16px;font-size:15px;line-height:1.6}.math-desk{gap:var(--math-gap);border-top:2px solid var(--math-ink);grid-template-columns:minmax(0,2fr) minmax(240px,1fr);display:grid}.math-sheet{min-width:0;padding-top:32px}.math-sheet>label,.math-sheet legend{font-size:18px;font-weight:650}.math-sheet select{width:100%;font:inherit;border:1px solid var(--math-ink);background:var(--math-paper);color:var(--math-ink);text-overflow:ellipsis;border-radius:8px;margin-block:12px 20px;padding:16px;font-size:17px;display:block}.math-primary{background:var(--math-pine);color:var(--math-paper);border:2px solid var(--math-ink);box-shadow:3px 3px 0 var(--math-ink);cursor:pointer;border-radius:12px;min-height:48px;margin:8px 4px 16px 0;padding:14px 24px;font-size:17px;font-weight:700}.math-room button:disabled{cursor:default;opacity:.65}.math-room :focus-visible{outline:3px solid var(--math-pine);outline-offset:4px}.math-ledger{background:var(--math-ground);border-inline:1px solid var(--math-rule);padding:28px}.math-ledger h2,.math-feedback h2{font-family:var(--math-display);margin:16px 0;font-size:27px;font-weight:620;line-height:1.2}.math-tally{font:500 64px/1 var(--font-geist-mono), monospace;margin:24px 0}.math-tally span{font:400 15px/1.5 var(--font-geist-sans), sans-serif;margin-top:10px;display:block}.math-ledger li{border-top:1px solid var(--math-rule);padding-block:12px;font-size:15px;list-style:none}.math-ledger small{color:var(--math-muted);margin-top:4px;display:block}.math-reading-link{border-block:2px solid var(--math-ink);color:var(--math-ink);text-underline-offset:4px;justify-content:space-between;margin-top:24px;padding-block:16px;font-weight:700;text-decoration:underline;display:flex}.math-running{color:var(--math-muted);justify-content:space-between;gap:24px;font-size:13px;display:flex}.math-sheet progress{width:100%;height:6px;accent-color:var(--math-pine);margin-block:12px 24px}.math-problem{font-family:var(--math-display);overflow-wrap:anywhere;margin-bottom:32px;font-size:clamp(25px,3vw,34px);font-weight:560;line-height:1.4}.math-options{grid-template-columns:1fr 1fr;gap:12px;margin-block:14px 24px;display:grid}.math-option{border:1px solid var(--math-rule);cursor:pointer;font:500 22px var(--font-geist-mono), monospace;border-radius:8px;align-items:center;gap:14px;padding:18px;display:flex;position:relative}.math-option input{width:20px;height:20px;accent-color:var(--math-pine)}.math-option-letter{color:var(--math-muted);font-size:12px}.math-option.is-chosen{border:2px solid var(--math-pine);background:var(--math-ground);padding:17px}.math-feedback{border-top:2px solid var(--math-pine);margin-top:24px;padding-top:8px}.math-solution{white-space:pre-line;overflow-wrap:anywhere;margin-block:20px;font-size:18px;line-height:1.8}.math-text-button{text-underline-offset:4px;cursor:pointer;min-height:44px;padding-block:12px;font-size:15px;text-decoration:underline;display:block}.math-error{color:var(--math-error);border-left:3px solid;margin-block:16px;padding-left:12px}@media (hover:hover){.math-primary:not(:disabled):hover{transform:translate(-1px,-1px)}.math-option:hover{border-color:var(--math-pine)}}@media (max-width:760px){.math-desk{grid-template-columns:1fr}.math-ledger{border-block:1px solid var(--math-rule)}.math-options{grid-template-columns:1fr}.math-running{flex-direction:column;gap:4px}}@media (prefers-color-scheme:dark){.math-room{--math-paper:#121c2b;--math-ground:#1e2a44;--math-ink:#fffbf0;--math-muted:#bbc8d6;--math-pine:#8fd5a3;--math-rule:#526077;--math-error:#ffb0a0}}