/* Vet Math Practice: engineering-pad green paper, graphite ink, a red grading pen. */
:root {
  --bg: #eef3ea;
  --paper: #fbfdf8;
  --grid: #dfe9d8;
  --ink: #1f261f;
  --muted: #4b584d;
  --line: #c6d3bf;
  --accent: #b3261e;
  --accent-ink: #ffffff;
  --accent-soft: #f7e3df;
  --ok: #1d6f36;
  --ok-soft: #e1f0e3;
  --close: #8a5a00;
  --close-soft: #f6ecd6;
  --focus: #1a5fb4;
  --mono: ui-monospace, "SF Mono", "Cascadia Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --r: 6px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #141a16;
    --paper: #1a211c;
    --grid: #222c25;
    --ink: #e5ece5;
    --muted: #a9b6ab;
    --line: #36443a;
    --accent: #f07b70;
    --accent-ink: #1b0d0b;
    --accent-soft: #3a1f1c;
    --ok: #7fd394;
    --ok-soft: #1c3324;
    --close: #f0c066;
    --close-soft: #3a2f17;
    --focus: #8ab8ff;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.55 var(--sans); }
.wrap { max-width: 860px; margin: 0 auto; padding: 0 16px; }
a { color: var(--accent); text-underline-offset: 2px; }
.skip { position: absolute; left: -999px; top: 8px; background: var(--paper); padding: 8px 12px; z-index: 10; }
.skip:focus { left: 8px; }
:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }
.sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

.hero { padding: 22px 0 8px; }
h1 { font-size: clamp(1.75rem, 5.2vw, 2.6rem); line-height: 1.1; margin: 0 0 8px; letter-spacing: -0.02em; font-weight: 800; }
.lede { margin: 0; color: var(--muted); max-width: 62ch; }
h2 { font-size: 1.3rem; line-height: 1.25; margin: 0 0 10px; letter-spacing: -0.01em; }

/* setup */
.setup { margin: 14px 0 8px; }
fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
legend { font-weight: 700; padding: 0; margin-bottom: 6px; }
.chips { display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr)); gap: 6px; }
.chip { position: relative; display: block; cursor: pointer; }
.chip input { position: absolute; opacity: 0; inset: 0; margin: 0; cursor: pointer; }
.chip span { display: block; min-height: 44px; padding: 7px 10px 7px 34px; border: 1.5px solid var(--line); border-radius: var(--r); background: var(--paper); line-height: 1.25; }
.chip span::before { content: ""; position: absolute; left: 10px; top: 11px; width: 15px; height: 15px; border: 2px solid var(--muted); border-radius: 3px; background: var(--paper); }
.chip b { display: block; font-size: 0.95rem; }
.chip small { display: block; color: var(--muted); font-size: 0.875rem; margin-top: 1px; }
.chip input:checked + span { border-color: var(--ink); }
.chip input:checked + span::before { background: var(--ink); border-color: var(--ink); }
.chip input:checked + span::after { content: ""; position: absolute; left: 15px; top: 13px; width: 5px; height: 9px; border: solid var(--paper); border-width: 0 2.5px 2.5px 0; transform: rotate(45deg); }
.chip input:focus-visible + span { outline: 3px solid var(--focus); outline-offset: 2px; }
.presets { display: flex; gap: 0 16px; flex-wrap: wrap; }
.setrow { display: flex; align-items: center; gap: 4px 12px; flex-wrap: wrap; margin-top: 10px; }
.chip .short { display: none; }
label.count { display: flex; align-items: center; gap: 8px; font-weight: 600; }
select, input { font: inherit; font-size: 16px; color: var(--ink); background: var(--paper); border: 1.5px solid var(--line); border-radius: var(--r); min-height: 44px; padding: 6px 10px; }
select { padding-right: 28px; max-width: 100%; }
.btn { font: inherit; font-weight: 650; min-height: 44px; padding: 8px 16px; border-radius: var(--r); border: 1.5px solid var(--ink); background: transparent; color: var(--ink); cursor: pointer; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-ink); }
.btn.small { min-height: 44px; padding: 6px 14px; }
.btn:hover { filter: brightness(0.95); }
.link { font: inherit; background: none; border: 0; padding: 10px 0; min-height: 44px; color: var(--accent); text-decoration: underline; text-underline-offset: 2px; cursor: pointer; }

.rules { margin-top: 12px; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.rules summary { cursor: pointer; padding: 11px 0; font-weight: 600; min-height: 44px; }
.rules summary span { font-weight: 400; color: var(--muted); }
.rule-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 10px 14px; }
.rule-grid label { display: flex; flex-direction: column; gap: 3px; font-size: 0.9rem; font-weight: 600; }
.rule-grid .wide { grid-column: 1 / -1; }
.hint { color: var(--muted); font-size: 0.9rem; margin: 8px 0 10px; }

.note { margin: 10px 0; padding: 10px 12px; border-left: 4px solid var(--close); background: var(--close-soft); border-radius: 0 var(--r) var(--r) 0; }
.note.info { border-left-color: var(--ok); background: var(--ok-soft); }

/* the sheet: graph paper */
.sheet { margin: 14px -16px 0; padding: 14px 16px 10px; background-color: var(--paper);
  background-image: linear-gradient(var(--grid) 1px, transparent 1px), linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 24px 24px; border-top: 2px solid var(--ink); border-bottom: 2px solid var(--ink); }
.sheet:focus { outline: none; }
.sheet-head { display: flex; justify-content: space-between; align-items: baseline; gap: 4px 12px; flex-wrap: wrap; }
.sheet-head h2 { margin: 0; }
.code { font-family: var(--mono); letter-spacing: 0.06em; }
.score { margin: 0; font-weight: 650; color: var(--muted); }
.caution { margin: 4px 0 6px; font-size: 0.9rem; color: var(--muted); }
.probs { list-style: none; margin: 0; padding: 0; }
.prob { padding: 12px 0 10px; border-top: 1px solid var(--line); }
.ptop { margin: 0; display: flex; align-items: baseline; gap: 10px; }
.num { font: 800 1.15rem var(--mono); color: var(--accent); min-width: 1.6em; }
.tag { font-size: 0.875rem; color: var(--muted); }
.q { margin: 2px 0 8px; max-width: 70ch; }
.rt { color: var(--muted); }
.arow { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; }
.ain { display: inline-flex; align-items: center; gap: 6px; }
.ain input { width: 9.5em; font-family: var(--mono); }
.ain .unit, .ain .pre { font-family: var(--mono); color: var(--muted); }
.fbwrap:empty { display: none; }
.fb { margin: 8px 0 0; padding: 6px 10px; border-radius: var(--r); display: inline-block; max-width: 100%; }
.fb.right { background: var(--ok-soft); color: var(--ok); }
.fb.close { background: var(--close-soft); color: var(--close); }
.fb.wrong, .fb.unread { background: var(--accent-soft); color: var(--accent); }
.prob.is-right .ain input { border-color: var(--ok); }
.prob.is-wrong .ain input { border-color: var(--accent); }
.work { margin-top: 4px; }
.work summary { cursor: pointer; color: var(--muted); font-size: 0.92rem; padding: 10px 0; min-height: 44px; display: flex; align-items: center; }
.work summary::marker { content: ""; }
.work summary::before { content: "+"; font-family: var(--mono); margin-right: 6px; }
.work[open] summary::before { content: "−"; }
.ans { margin: 0 0 4px; }
.ans b { font-family: var(--mono); }
.steps { margin: 0 0 4px; padding-left: 1.9em; font-family: var(--mono); font-size: 0.88rem; line-height: 1.6; overflow-wrap: anywhere; }
.sheet-foot { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; border-top: 1px solid var(--line); padding-top: 10px; }

.share { margin: 16px 0 8px; }
.print-row { display: flex; align-items: flex-end; gap: 8px 10px; flex-wrap: wrap; }
.print-row label { display: flex; flex-direction: column; gap: 3px; font-size: 0.9rem; font-weight: 600; }
.share-out label { display: flex; flex-direction: column; gap: 3px; font-size: 0.9rem; font-weight: 600; }
.share-out input { width: 100%; font-family: var(--mono); font-size: 16px; }
.recent { margin-top: 12px; border-top: 1px solid var(--line); }
.recent summary { cursor: pointer; padding: 11px 0; font-weight: 600; min-height: 44px; }
.recent ul { list-style: none; margin: 0; padding: 0; }
.recent li { display: flex; justify-content: space-between; align-items: center; gap: 10px; border-top: 1px solid var(--line); padding: 4px 0; }
.recent small { display: block; color: var(--muted); }

.toast { position: fixed; left: 50%; bottom: 16px; transform: translate(-50%, 140%); background: var(--ink); color: var(--bg); padding: 10px 14px; border-radius: var(--r); max-width: calc(100% - 32px); transition: transform 0.2s; z-index: 20; }
.toast.on { transform: translate(-50%, 0); }
@media (prefers-reduced-motion: reduce) { .toast { transition: none; } }

/* content */
.content { padding: 18px 0 8px; }
.content h2 { margin-top: 26px; }
.content p { max-width: 70ch; }
.tablewrap { overflow-x: auto; }
table.src { border-collapse: collapse; width: 100%; font-size: 0.93rem; }
.src th, .src td { text-align: left; vertical-align: top; padding: 7px 8px 7px 0; border-bottom: 1px solid var(--line); }
.src td:nth-child(2) { white-space: nowrap; font-family: var(--mono); font-size: 0.88rem; }
.checked { color: var(--muted); font-size: 0.9rem; }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { cursor: pointer; padding: 11px 0; font-weight: 600; min-height: 44px; }
.faq details p { margin: 0 0 12px; }
.disclaimer { margin-top: 22px; padding-left: 12px; border-left: 4px solid var(--accent); }
.sources { font-size: 0.9rem; color: var(--muted); overflow-wrap: anywhere; }

footer { border-top: 1px solid var(--line); margin-top: 20px; padding: 16px 0 28px; color: var(--muted); font-size: 0.92rem; }
.indep { margin: 0 0 10px; }
.sb-footer p { margin: 6px 0; }
.sb-more { line-height: 1.8; }
.sb-footer a { color: var(--ink); }

@media (max-width: 600px) {
  .chips { display: flex; flex-wrap: wrap; gap: 6px; }
  .chip small, .chip .long { display: none; }
  .chip .short { display: block; }
  .chip span { padding: 10px 12px 10px 34px; }
  .hero { padding-top: 14px; }
}
@media (max-width: 480px) {
  body { font-size: 16.5px; }
  .ain input { width: 8em; }
  .src td:nth-child(2) { white-space: normal; }
}

/* print: only the worksheet and key */
.print-root { display: none; }
@page { margin: 0.55in 0.6in; }
@media print {
  :root { --ink: #000; --muted: #333; --line: #999; }
  body { background: #fff; color: #000; font: 11pt/1.4 var(--sans); }
  main, footer, .toast, .skip { display: none !important; }
  .print-root { display: block; }
  table.pt { width: 100%; border-collapse: collapse; }
  table.pt > tbody > tr > td, table.pt > thead > tr > td { padding: 0; }
  .prun { font: 9pt var(--mono); color: #555; text-align: right; padding-bottom: 6pt !important; }
  .ph { display: flex; justify-content: space-between; align-items: baseline; border-bottom: 2pt solid #000; margin-bottom: 8pt; }
  .ph h2 { font-size: 16pt; margin: 0; }
  .ph p { margin: 0; font: 11pt var(--mono); }
  .pmeta { display: flex; justify-content: space-between; gap: 12pt; margin: 6pt 0 10pt; }
  .pconv { border: 1pt solid #000; padding: 5pt 8pt; margin: 0 0 6pt; font-size: 10pt; }
  .pconv b { margin-right: 4pt; }
  .pnote { font-size: 9.5pt; color: #333; margin: 0 0 8pt; }
  .pq { margin: 0; padding-left: 22pt; }
  .pq > li { break-inside: avoid; page-break-inside: avoid; min-height: 1.3in; padding: 4pt 0 6pt; border-bottom: 0.75pt solid #999; }
  .pq > li p { margin: 0; }
  .pq .pans { margin-top: 0.45in; text-align: right; font-family: var(--mono); }
  .psheet + .pkey { break-before: page; page-break-before: always; }
  .pk { margin: 0; padding-left: 22pt; }
  .pk > li { break-inside: avoid; page-break-inside: avoid; padding: 3pt 0 5pt; border-bottom: 0.75pt solid #bbb; }
  .pk p { margin: 0; }
  .pkq { font-size: 9.5pt; color: #333; }
  .pka { font: 700 11pt var(--mono); margin-top: 2pt !important; }
  .pks { margin: 1pt 0 0; padding-left: 16pt; font: 9.5pt/1.35 var(--mono); }
}