/* Answer-sheet look: form-blue print on cool paper, graphite marks, green/red only when grading. */
:root {
  --paper: #f1f4f3;
  --sheet: #fbfcfc;
  --ink: #1f2328;
  --ink-soft: #545b64;
  --print: #2c5c9a;
  --print-soft: #c3d3ea;
  --print-wash: #e6eef8;
  --graphite: #2e3136;
  --on-graphite: #fbfcfc;
  --ok: #1d7646;
  --ok-wash: #e0f1e6;
  --bad: #b2362e;
  --bad-wash: #f7e2df;
  --flag: #a86f00;
  --flag-wash: #fbefd6;
  --focus: #2c5c9a;

  --font-body: "Atkinson Hyperlegible", "Segoe UI", system-ui, sans-serif;
  --font-num: "Barlow Condensed", "Arial Narrow", "Roboto Condensed", sans-serif;

  --step--1: 0.875rem;
  --step-0: 1rem;
  --step-1: 1.15rem;
  --step-2: 1.5rem;
  --step-3: 2.25rem;
  --step-4: 4.5rem;

  --radius-s: 4px;
  --radius-m: 10px;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #111417;
    --sheet: #181c20;
    --ink: #e6e9ed;
    --ink-soft: #a3abb5;
    --print: #8fb3e6;
    --print-soft: #34465f;
    --print-wash: #1c2633;
    --graphite: #e6e9ed;
    --on-graphite: #111417;
    --ok: #63c48f;
    --ok-wash: #16301f;
    --bad: #f08a80;
    --bad-wash: #3a1d1a;
    --flag: #e5b450;
    --flag-wash: #382a0d;
    --focus: #8fb3e6;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --paper: #111417;
  --sheet: #181c20;
  --ink: #e6e9ed;
  --ink-soft: #a3abb5;
  --print: #8fb3e6;
  --print-soft: #34465f;
  --print-wash: #1c2633;
  --graphite: #e6e9ed;
  --on-graphite: #111417;
  --ok: #63c48f;
  --ok-wash: #16301f;
  --bad: #f08a80;
  --bad-wash: #3a1d1a;
  --flag: #e5b450;
  --flag-wash: #382a0d;
  --focus: #8fb3e6;
  color-scheme: dark;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: var(--step-0);
  line-height: 1.55;
}

main { max-width: 1180px; margin: 0 auto; padding: 24px 16px 64px; }

[hidden] { display: none !important; }

h1, h2 { font-family: var(--font-num); font-weight: 600; line-height: 1.1; color: var(--print); margin: 0; }
h1 { font-size: var(--step-3); }
h2 { font-size: var(--step-2); margin-bottom: 12px; }

code, kbd {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: 0.9em;
  background: var(--print-wash);
  border-radius: var(--radius-s);
  padding: 0.05em 0.35em;
}

a { color: var(--print); text-underline-offset: 2px; }

:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }

.row { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; }
.row.tight { gap: 4px 16px; }
.hint { color: var(--ink-soft); font-size: var(--step--1); font-family: var(--font-body); font-weight: 400; }

/* Buttons */
.btn {
  font: inherit;
  font-weight: 700;
  border-radius: var(--radius-s);
  border: 2px solid var(--print);
  padding: 9px 16px;
  cursor: pointer;
  background: transparent;
  color: var(--print);
  min-height: 44px;
}
.btn.primary { background: var(--print); color: var(--sheet); }
.btn.primary:hover { filter: brightness(1.08); }
.btn.ghost:hover { background: var(--print-wash); }
.btn.link { border: 0; padding: 4px 0; min-height: 0; text-decoration: underline; font-weight: 400; }
.btn.big { font-size: var(--step-1); padding: 12px 28px; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

/* Setup */
.setup-head { padding: 24px 0 8px; max-width: 70ch; }
.setup-head h1 { font-size: var(--step-4); font-weight: 700; letter-spacing: -0.01em; }
.lede { font-size: var(--step-1); color: var(--ink-soft); margin: 8px 0 0; }

.setup-form { display: grid; gap: 28px; margin-top: 28px; max-width: 900px; }

fieldset { border: 0; padding: 0; margin: 0; }
legend { font-family: var(--font-num); font-size: var(--step-2); font-weight: 600; color: var(--print); margin-bottom: 10px; padding: 0; }

.modes { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 12px; }
.modes legend { grid-column: 1 / -1; }
.mode {
  position: relative;
  display: grid;
  grid-template-columns: 28px 1fr;
  gap: 2px 12px;
  padding: 16px;
  border: 2px solid var(--print-soft);
  border-radius: var(--radius-m);
  background: var(--sheet);
  cursor: pointer;
}
.mode input { grid-row: 1 / 3; width: 22px; height: 22px; margin: 2px 0 0; accent-color: var(--print); }
.mode-name { font-weight: 700; font-size: var(--step-1); }
.mode-desc { color: var(--ink-soft); font-size: var(--step--1); }
.mode:has(input:checked) { border-color: var(--print); box-shadow: inset 0 0 0 1px var(--print); }

.opts { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 16px 20px; align-items: end; }
.field { display: grid; gap: 6px; font-weight: 700; }
.field select {
  font: inherit;
  font-weight: 400;
  padding: 9px 10px;
  border: 2px solid var(--print-soft);
  border-radius: var(--radius-s);
  background: var(--sheet);
  color: var(--ink);
  min-height: 44px;
}
.check { display: flex; gap: 10px; align-items: flex-start; grid-column: 1 / -1; }
.check input { width: 20px; height: 20px; margin-top: 3px; accent-color: var(--print); }

.module-list { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 2px 20px; margin-top: 8px; }
.module-list label { display: flex; gap: 10px; align-items: baseline; padding: 6px 0; border-bottom: 1px solid var(--print-soft); cursor: pointer; }
.module-list input { accent-color: var(--print); width: 18px; height: 18px; flex: none; transform: translateY(3px); }
.module-list .n { font-family: var(--font-num); font-weight: 600; color: var(--print); min-width: 1.6em; }
.module-list .c { margin-left: auto; color: var(--ink-soft); font-size: var(--step--1); }

.form-error { color: var(--bad); font-weight: 700; margin: 0; }

.resume { margin-top: 20px; padding: 14px 16px; border-left: 4px solid var(--flag); background: var(--flag-wash); max-width: 900px; }
.resume p { margin: 0 0 10px; }

.history { margin-top: 48px; max-width: 900px; }

table { border-collapse: collapse; width: 100%; font-size: var(--step--1); }
th, td { text-align: left; padding: 8px 10px 8px 0; border-bottom: 1px solid var(--print-soft); }
th { color: var(--print); font-weight: 700; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }

/* Exam */
.exam-bar {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 0;
  background: var(--paper);
  border-bottom: 2px solid var(--print-soft);
}
.counter { margin: 0; font-family: var(--font-num); font-size: var(--step-2); font-weight: 600; color: var(--print); white-space: nowrap; }
.counter .of { font-size: var(--step-0); color: var(--ink-soft); margin-left: 6px; font-weight: 500; }
.progress { flex: 1; height: 6px; background: var(--print-wash); border-radius: 3px; overflow: hidden; min-width: 40px; }
.progress span { display: block; height: 100%; width: 0; background: var(--print); transition: width 0.25s ease; }
.timer { margin: 0; font-family: var(--font-num); font-size: var(--step-2); font-weight: 600; font-variant-numeric: tabular-nums; min-width: 5ch; text-align: right; }
.timer.low { color: var(--bad); }
.sheet-toggle { display: none; }

.exam-body { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 32px; margin-top: 24px; align-items: start; }

.question { background: var(--sheet); border: 1px solid var(--print-soft); border-radius: var(--radius-m); padding: 28px 32px; }
.q-head { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.q-num {
  font-family: var(--font-num);
  font-size: var(--step-4);
  font-weight: 700;
  line-height: 0.9;
  color: var(--print);
  font-variant-numeric: tabular-nums;
}
.q-tag { font-family: var(--font-num); font-weight: 600; border: 2px solid var(--print); color: var(--print); border-radius: var(--radius-s); padding: 0 6px; }
.q-flagged { color: var(--flag); font-weight: 700; font-size: var(--step--1); }
.q-stem { font-size: var(--step-1); line-height: 1.6; max-width: 68ch; margin: 18px 0 8px; }
.q-instr { margin: 0 0 14px; color: var(--print); font-weight: 700; font-size: var(--step--1); min-height: 1.2em; }

.options { display: grid; gap: 8px; max-width: 72ch; }
.opt {
  display: grid;
  grid-template-columns: 36px 1fr;
  gap: 14px;
  align-items: center;
  text-align: left;
  font: inherit;
  color: inherit;
  background: transparent;
  border: 1px solid transparent;
  border-radius: var(--radius-m);
  padding: 8px 12px 8px 6px;
  cursor: pointer;
}
.opt:hover:not(:disabled) { background: var(--print-wash); }
.opt:disabled { cursor: default; }
.bubble {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 2px solid var(--print-soft);
  display: grid;
  place-items: center;
  font-family: var(--font-num);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--print);
  background: var(--sheet);
  transition: background-color 0.12s ease, border-color 0.12s ease, transform 0.12s ease;
}
.opt[aria-checked="true"] .bubble {
  background: var(--graphite);
  border-color: var(--graphite);
  color: var(--on-graphite);
  transform: scale(1.06);
}
.opt.correct { background: var(--ok-wash); border-color: var(--ok); }
.opt.correct .bubble { border-color: var(--ok); }
.opt.wrong { background: var(--bad-wash); border-color: var(--bad); }
.opt.correct[aria-checked="true"] .bubble { background: var(--ok); border-color: var(--ok); color: var(--sheet); }
.opt.wrong[aria-checked="true"] .bubble { background: var(--bad); border-color: var(--bad); color: var(--sheet); }

.feedback { margin-top: 16px; padding: 12px 14px; border-left: 4px solid var(--print); background: var(--print-wash); max-width: 72ch; }
.feedback.ok { border-color: var(--ok); background: var(--ok-wash); }
.feedback.bad { border-color: var(--bad); background: var(--bad-wash); }
.feedback p { margin: 0 0 6px; }
.feedback p:last-child { margin-bottom: 0; }

.q-nav { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 24px; }
.q-nav #next, .q-nav #confirm { margin-left: auto; }
.q-nav #confirm + #next { margin-left: 0; }
#flag[aria-pressed="true"] { background: var(--flag-wash); border-color: var(--flag); color: var(--flag); }
.keys { margin: 18px 0 0; color: var(--ink-soft); font-size: var(--step--1); }

/* Answer sheet */
.sheet { position: sticky; top: 76px; background: var(--sheet); border: 1px solid var(--print-soft); border-radius: var(--radius-m); padding: 16px; max-height: calc(100vh - 96px); overflow: auto; }
.sheet h2 { font-size: var(--step-1); margin-bottom: 4px; }
.sheet-sum { margin: 0 0 10px; font-size: var(--step--1); color: var(--ink-soft); }
.sheet-grid { list-style: none; margin: 0; padding: 0; display: grid; grid-template-columns: 1fr 1fr; gap: 2px 10px; }
.sheet-grid button {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 6px;
  font: inherit;
  background: none;
  border: 0;
  border-radius: var(--radius-s);
  padding: 3px 4px;
  cursor: pointer;
  color: var(--ink);
}
.sheet-grid button:hover { background: var(--print-wash); }
.sheet-grid .n { font-family: var(--font-num); font-weight: 600; color: var(--print); width: 2ch; text-align: right; font-variant-numeric: tabular-nums; }
.sheet-grid .dots { display: flex; gap: 3px; }
.sheet-grid .dot { width: 11px; height: 11px; border-radius: 50%; border: 1.5px solid var(--print-soft); }
.sheet-grid .dot.on { background: var(--graphite); border-color: var(--graphite); }
.sheet-grid .current { background: var(--print-wash); box-shadow: inset 3px 0 0 var(--print); }
.sheet-grid .flagged .n { color: var(--flag); }
.sheet-grid .flagged::after { content: ""; width: 6px; height: 6px; border-radius: 50%; background: var(--flag); margin-left: auto; }
.sheet-grid .graded-ok .dot.on { background: var(--ok); border-color: var(--ok); }
.sheet-grid .graded-bad .dot.on { background: var(--bad); border-color: var(--bad); }

.confirm-end { position: fixed; inset: 0; background: rgb(0 0 0 / 0.45); display: grid; place-items: center; padding: 16px; z-index: 20; }
.confirm-box { background: var(--sheet); border-radius: var(--radius-m); padding: 24px; max-width: 460px; border-top: 6px solid var(--print); }
.confirm-box p { margin: 10px 0 18px; }

/* Result */
.score { display: flex; flex-wrap: wrap; align-items: flex-end; gap: 12px 32px; padding: 24px 0 20px; border-bottom: 2px solid var(--print-soft); margin-bottom: 20px; }
.score-main { margin: 0; font-family: var(--font-num); font-weight: 700; font-size: clamp(4.5rem, 16vw, 9rem); line-height: 0.85; color: var(--print); font-variant-numeric: tabular-nums; }
.score-main .slash { color: var(--print-soft); margin: 0 0.04em; }
.score-side { padding-bottom: 6px; }
.score-pct { margin: 0; font-family: var(--font-num); font-size: var(--step-3); font-weight: 600; line-height: 1; }
.verdict { margin: 6px 0 0; font-weight: 700; font-size: var(--step-1); }
.verdict.ok { color: var(--ok); }
.verdict.bad { color: var(--bad); }
.score-meta { margin: 4px 0 0; color: var(--ink-soft); font-size: var(--step--1); max-width: 52ch; }

.breakdown { margin-top: 36px; max-width: 900px; }

.bars { display: grid; gap: 12px; }
.bar { display: grid; grid-template-columns: minmax(150px, 260px) 1fr 7ch; gap: 12px; align-items: center; }
.bar-label { font-weight: 700; }
.bar-label small { display: block; font-weight: 400; color: var(--ink-soft); }
.bar-track { position: relative; height: 14px; background: var(--print-wash); border-radius: 7px; overflow: hidden; }
.bar-fill { position: absolute; inset: 0 auto 0 0; background: var(--bad); border-radius: 7px; }
.bar-fill.ok { background: var(--ok); }
.bar-track .goal { position: absolute; top: -3px; bottom: -3px; left: 75%; width: 2px; background: var(--ink); opacity: 0.55; }
.bar-val { font-family: var(--font-num); font-weight: 600; font-size: var(--step-1); text-align: right; font-variant-numeric: tabular-nums; }

.mod-table td:nth-child(2), .mod-table td:nth-child(3), .mod-table th:nth-child(2), .mod-table th:nth-child(3) { text-align: right; font-variant-numeric: tabular-nums; }
.mod-table .low { color: var(--bad); font-weight: 700; }

.review { margin-top: 40px; max-width: 900px; }
.filters { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 16px; }
.filters button {
  font: inherit;
  border: 2px solid var(--print-soft);
  background: var(--sheet);
  color: var(--ink);
  border-radius: 999px;
  padding: 6px 14px;
  cursor: pointer;
  min-height: 40px;
}
.filters button[aria-selected="true"] { border-color: var(--print); background: var(--print); color: var(--sheet); }

.review-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 14px; }
.review-item { background: var(--sheet); border: 1px solid var(--print-soft); border-left-width: 5px; border-radius: var(--radius-m); padding: 16px 18px; }
.review-item.ok { border-left-color: var(--ok); }
.review-item.bad { border-left-color: var(--bad); }
.review-item.blank { border-left-color: var(--flag); }
.review-item .rh { display: flex; flex-wrap: wrap; gap: 6px 14px; align-items: baseline; font-size: var(--step--1); color: var(--ink-soft); }
.review-item .rh .n { font-family: var(--font-num); font-size: var(--step-2); font-weight: 700; color: var(--print); }
.review-item .stem { margin: 6px 0 10px; max-width: 72ch; }
.review-item ul { list-style: none; padding: 0; margin: 0 0 10px; display: grid; gap: 4px; }
.review-item li { display: grid; grid-template-columns: 26px 1fr auto; gap: 10px; align-items: baseline; padding: 4px 8px; border-radius: var(--radius-s); }
.review-item li .l { font-family: var(--font-num); font-weight: 600; color: var(--print); }
.review-item li.is-correct { background: var(--ok-wash); }
.review-item li.is-wrong { background: var(--bad-wash); }
.review-item li .tag { font-size: var(--step--1); font-weight: 700; }
.review-item li.is-correct .tag { color: var(--ok); }
.review-item li.is-wrong .tag { color: var(--bad); }
.review-item .expl { margin: 0 0 6px; max-width: 72ch; }
.review-item .src { margin: 0; font-size: var(--step--1); color: var(--ink-soft); }
.empty { color: var(--ink-soft); }

/* Small screens */
@media (max-width: 900px) {
  .exam-body { grid-template-columns: 1fr; }
  .sheet-toggle { display: inline-block; }
  .sheet { display: none; position: fixed; inset: auto 0 0 0; top: auto; max-height: 60vh; z-index: 10; border-radius: var(--radius-m) var(--radius-m) 0 0; box-shadow: 0 -8px 24px rgb(0 0 0 / 0.2); }
  .sheet.open { display: block; }
  .sheet-grid { grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); }
  .progress { display: none; }
}

@media (max-width: 600px) {
  main { padding-top: 12px; }
  .setup-head h1 { font-size: var(--step-3); }
  .question { padding: 18px 16px; }
  .q-num { font-size: var(--step-3); }
  .exam-bar { gap: 8px; flex-wrap: wrap; }
  .exam-bar .btn { padding: 6px 10px; }
  .timer { margin-left: auto; }
  .bar { grid-template-columns: 1fr 6ch; }
  .bar-track { grid-column: 1 / -1; grid-row: 2; }
  .q-nav .btn { flex: 1 1 auto; }
  .q-nav #next, .q-nav #confirm { margin-left: 0; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none !important; animation: none !important; }
}