:root {
  --fg: #1d2330;
  --muted: #5b6475;
  --bg: #f7f8fa;
  --card: #fff;
  --accent: #2457c5;
  --accent-soft: #e8eefb;
  --border: #dde1e8;
  --good: #1a7f4b;
  --good-soft: #e6f4ec;
  --bad: #b42318;
  --bad-soft: #fdecea;
  --warn: #b45309;
  --warn-soft: #fff4e5;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; font-family: system-ui, -apple-system, "Segoe UI", sans-serif; color: var(--fg); background: var(--bg); line-height: 1.5; }
a { color: var(--accent); }
h1 { font-size: 1.6rem; margin: 0 0 16px; }
h2 { font-size: 1.2rem; margin: 28px 0 12px; }

/* Header */
.site-header { background: var(--card); border-bottom: 1px solid var(--border); }
.site-header nav { max-width: 1100px; margin: 0 auto; padding: 12px 16px; display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.site-header .brand { font-weight: 700; color: var(--fg); text-decoration: none; margin-right: auto; }
.site-header a, .linklike { color: var(--accent); text-decoration: none; background: none; border: 0; font: inherit; cursor: pointer; padding: 0; }
main { max-width: 1100px; margin: 32px auto; padding: 0 16px; }

/* Shared pieces */
.card { background: var(--card); border: 1px solid var(--border); border-radius: 8px; padding: 20px; }
.card.narrow { max-width: 440px; }
.btn { display: inline-block; background: var(--accent); color: #fff; border: 1px solid var(--accent); border-radius: 6px; padding: 9px 18px; font: inherit; font-weight: 600; cursor: pointer; text-decoration: none; }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.secondary { background: var(--card); color: var(--accent); }
.muted { color: var(--muted); font-size: .92em; }
.messages { list-style: none; padding: 0; margin: 0 0 20px; }
.messages li { padding: 10px 14px; border-radius: 6px; background: var(--accent-soft); margin-bottom: 8px; }
.messages li.error { background: var(--bad-soft); color: var(--bad); }
form p { margin: 0 0 14px; }
form label { display: block; font-weight: 600; margin-bottom: 4px; }
form input[type=text], form input[type=email], form input[type=password] { width: 100%; padding: 8px 10px; border: 1px solid var(--border); border-radius: 6px; font: inherit; }
.helptext { color: var(--muted); font-size: .9em; }
.errorlist { color: var(--bad); padding-left: 18px; }
table.data { width: 100%; border-collapse: collapse; background: var(--card); }
table.data th, table.data td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--border); }
table.data th { font-size: .85em; color: var(--muted); font-weight: 600; }
.table-wrap { overflow-x: auto; border: 1px solid var(--border); border-radius: 8px; }

/* Dashboard */
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px; }
.test-card { display: flex; flex-direction: column; gap: 6px; }
.test-card h3 { margin: 0; font-size: 1.05rem; }
.test-card form { margin-top: auto; padding-top: 10px; }
.banner { background: var(--warn-soft); border: 1px solid #f3d7b0; border-radius: 8px; padding: 14px 18px; margin-bottom: 24px; display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
.banner .btn { margin-left: auto; }

/* Question content */
.content p { margin: 0 0 12px; }
.content table { border-collapse: collapse; margin: 8px 0 14px; }
.content th, .content td { border: 1px solid var(--border); padding: 6px 10px; text-align: center; }
.content th { background: var(--bg); }
.content ul { padding-left: 22px; margin: 0 0 12px; }
.katex { font-size: 1.05em; }

/* Test-taking page */
body.taking main { margin-top: 0; max-width: 1200px; }
.test-bar { position: sticky; top: 0; z-index: 10; background: var(--card); border-bottom: 1px solid var(--border); margin: 0 -16px 20px; padding: 10px 16px; display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.test-bar .title { font-weight: 600; margin-right: auto; }
.timer { font-variant-numeric: tabular-nums; font-weight: 700; font-size: 1.1rem; padding: 4px 10px; border-radius: 6px; }
.timer.low { background: var(--bad-soft); color: var(--bad); }
.save-status { font-size: .85em; color: var(--muted); min-width: 70px; text-align: right; }
.save-status.error { color: var(--bad); }
.question { display: grid; gap: 28px; }
.question.has-passage { grid-template-columns: 1fr 1fr; }
.question .passage { border-right: 1px solid var(--border); padding-right: 28px; }
@media (max-width: 800px) {
  .question.has-passage { grid-template-columns: 1fr; }
  .question .passage { border-right: 0; padding-right: 0; border-bottom: 1px solid var(--border); padding-bottom: 16px; }
}
.q-head { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; padding-bottom: 8px; border-bottom: 2px dashed var(--border); }
.q-num { background: var(--fg); color: #fff; font-weight: 700; border-radius: 4px; padding: 2px 10px; }
.flag-btn { background: none; border: 1px solid transparent; border-radius: 6px; padding: 4px 8px; font: inherit; cursor: pointer; color: var(--muted); }
.flag-btn[aria-pressed=true] { color: var(--warn); border-color: var(--warn); background: var(--warn-soft); font-weight: 600; }
.choices { display: grid; gap: 10px; margin-top: 16px; }
.choice { display: flex; align-items: flex-start; gap: 12px; border: 1px solid var(--border); border-radius: 8px; padding: 12px 14px; cursor: pointer; background: var(--card); }
.choice:hover { border-color: var(--accent); }
.choice input { position: absolute; opacity: 0; pointer-events: none; }
.choice .letter { flex: none; width: 28px; height: 28px; border-radius: 50%; border: 2px solid var(--fg); display: grid; place-items: center; font-weight: 700; font-size: .9em; }
.choice:has(input:checked) { border-color: var(--accent); box-shadow: 0 0 0 1px var(--accent); background: var(--accent-soft); }
.choice:has(input:checked) .letter { background: var(--accent); border-color: var(--accent); color: #fff; }
.choice:has(input:focus-visible) { outline: 2px solid var(--accent); outline-offset: 2px; }
.spr label { display: block; font-weight: 600; }
.spr input { font: inherit; font-size: 1.2rem; width: 9ch; padding: 8px 10px; border: 2px solid var(--fg); border-radius: 6px; margin-top: 12px; }
.spr .muted { margin-top: 8px; }
.test-nav { display: flex; align-items: center; gap: 12px; margin-top: 28px; padding-top: 16px; border-top: 1px solid var(--border); }
.test-nav .spacer { margin-right: auto; }
.navigator { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0 20px; }
.navigator button { width: 42px; height: 42px; border: 1px dashed var(--fg); border-radius: 6px; background: var(--card); font: inherit; font-weight: 600; cursor: pointer; position: relative; }
.navigator button.answered { background: var(--accent); border: 1px solid var(--accent); color: #fff; }
.navigator button.current { outline: 2px solid var(--fg); outline-offset: 2px; }
.navigator button.flagged::after { content: ""; position: absolute; top: -5px; right: -5px; width: 12px; height: 12px; border-radius: 50%; background: var(--warn); border: 2px solid var(--card); }
.legend { display: flex; gap: 16px; flex-wrap: wrap; font-size: .85em; color: var(--muted); }
dialog { border: 1px solid var(--border); border-radius: 10px; padding: 24px; max-width: min(560px, calc(100vw - 32px)); }
dialog::backdrop { background: rgb(0 0 0 / .35); }

/* Results */
.score-head { display: flex; gap: 32px; align-items: center; flex-wrap: wrap; }
.score-big { font-size: 3rem; font-weight: 800; line-height: 1; }
.bar { height: 8px; background: var(--border); border-radius: 4px; overflow: hidden; min-width: 80px; }
.bar span { display: block; height: 100%; background: var(--accent); }
.review-item { border: 1px solid var(--border); border-radius: 8px; background: var(--card); margin-bottom: 10px; }
.review-item summary { padding: 12px 16px; cursor: pointer; display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.review-item .body { padding: 0 16px 16px; }
.pill { font-size: .8em; font-weight: 700; border-radius: 999px; padding: 2px 10px; }
.pill.good { background: var(--good-soft); color: var(--good); }
.pill.bad { background: var(--bad-soft); color: var(--bad); }
.pill.skip { background: var(--bg); color: var(--muted); border: 1px solid var(--border); }
.review-choice { border: 1px solid var(--border); border-radius: 8px; padding: 10px 14px; margin-bottom: 8px; }
.review-choice.correct { border-color: var(--good); background: var(--good-soft); }
.review-choice.picked-wrong { border-color: var(--bad); background: var(--bad-soft); }
.review-choice .rationale { color: var(--muted); font-size: .92em; margin-top: 4px; }
.explanation { background: var(--accent-soft); border-radius: 8px; padding: 12px 16px; margin-top: 12px; }
fieldset.choices { border: 0; padding: 0; margin: 16px 0 0; min-width: 0; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.timer.hidden-timer { visibility: hidden; }
.site-footer { max-width: 1100px; margin: 48px auto 24px; padding: 16px; border-top: 1px solid var(--border); color: var(--muted); font-size: .8rem; }