:root {
  --bg: #f6f5f1;
  --surface: #ffffff;
  --surface-2: #efede7;
  --ink: #1b1e23;
  --muted: #5a616d;
  --line: #e0ddd5;
  --accent: #1d4f7c;
  --accent-ink: #ffffff;
  --accent-soft: #e3ecf5;
  --ok: #1d7444;
  --ok-soft: #e2f2e8;
  --bad: #b02a22;
  --bad-soft: #f8e4e2;
  --flag: #9a6500;
  --flag-soft: #f8edd6;
  --radius: 12px;
  --shadow: 0 1px 2px rgba(20, 24, 31, .06), 0 4px 16px rgba(20, 24, 31, .05);
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111317;
    --surface: #1a1d22;
    --surface-2: #22262c;
    --ink: #e8e9eb;
    --muted: #a2a8b3;
    --line: #2d3138;
    --accent: #8db8e3;
    --accent-ink: #0b1826;
    --accent-soft: #1d2b3a;
    --ok: #6fcf97;
    --ok-soft: #173326;
    --bad: #f08a80;
    --bad-soft: #3a1d1b;
    --flag: #e7b75a;
    --flag-soft: #3a2f17;
    --shadow: none;
    color-scheme: dark;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.6 var(--font);
}
a { color: var(--accent); }
img { max-width: 100%; height: auto; }
.wrap { max-width: 960px; margin: 0 auto; padding: 0 16px; }
.narrow { max-width: 760px; }

.preview {
  background: var(--flag-soft);
  color: var(--ink);
  font-size: 14px;
  text-align: center;
  padding: 6px 16px;
  border-bottom: 1px solid var(--line);
}

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 10px 18px;
  border-radius: 10px; border: 1px solid var(--accent);
  background: var(--accent); color: var(--accent-ink);
  font: 600 15px/1.2 var(--font); text-decoration: none; cursor: pointer;
}
.btn:hover { filter: brightness(1.08); }
.btn.ghost { background: transparent; color: var(--accent); }
.btn.quiet { background: var(--surface); color: var(--ink); border-color: var(--line); }
.btn[disabled], .btn.disabled { opacity: .5; cursor: not-allowed; pointer-events: none; }
.btn.small { min-height: 36px; padding: 6px 12px; font-size: 14px; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px;
}
.muted { color: var(--muted); }
.small { font-size: 14px; }
.eyebrow { font-size: 13px; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); font-weight: 600; margin: 0 0 8px; }
h1, h2, h3 { line-height: 1.25; margin: 0 0 12px; }
h2 { font-size: 26px; }
h3 { font-size: 19px; }

/* Landing */
.hero { padding: 56px 0 40px; border-bottom: 1px solid var(--line); }
.hero h1 { font-family: var(--serif); font-size: clamp(34px, 6vw, 52px); font-weight: 700; letter-spacing: -.01em; margin-bottom: 14px; }
.hero .sub { font-family: var(--serif); font-size: clamp(18px, 2.4vw, 22px); color: var(--muted); max-width: 680px; margin: 0 0 18px; }
.hero .by { margin: 0 0 26px; font-weight: 600; }
.actions { display: flex; flex-wrap: wrap; gap: 10px; }
section.block { padding: 44px 0; border-bottom: 1px solid var(--line); }
section.block > .wrap > p.lead { max-width: 680px; color: var(--muted); margin: 0 0 22px; }
.grid2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
.exam-card h3 { margin-bottom: 4px; }
.facts { list-style: none; padding: 0; margin: 10px 0 18px; display: flex; flex-wrap: wrap; gap: 6px 14px; color: var(--muted); font-size: 14px; }
.live-list { list-style: none; padding: 0; margin: 0 0 18px; display: grid; gap: 10px; }
.live-list li { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 16px; align-items: center; }
.live-when { font-weight: 600; }
.split { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
footer.site { padding: 32px 0 48px; color: var(--muted); font-size: 13px; }
footer.site p { margin: 0 0 8px; max-width: 720px; }

/* Exam app */
.topbar {
  position: sticky; top: 0; z-index: 10;
  background: var(--surface); border-bottom: 1px solid var(--line);
}
.topbar .wrap { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 56px; }
.topbar a.home { font-weight: 700; text-decoration: none; color: var(--ink); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.topbar .meta { display: flex; gap: 10px; align-items: center; font-variant-numeric: tabular-nums; }
.timer { font-weight: 700; padding: 4px 10px; border-radius: 8px; background: var(--surface-2); }
.timer.low { background: var(--bad-soft); color: var(--bad); }
.progress { height: 4px; background: var(--surface-2); }
.progress > i { display: block; height: 100%; background: var(--accent); width: 0; transition: width .2s; }
main.app { padding: 22px 0 120px; }
.qhead { display: flex; justify-content: space-between; align-items: center; gap: 10px; margin-bottom: 12px; flex-wrap: wrap; }
.qnum { font-weight: 700; }
.stem p { margin: 0 0 12px; }
.hint { font-size: 14px; font-weight: 600; color: var(--accent); margin: 4px 0 12px; }
figure.fig { margin: 8px 0 16px; background: #fff; border: 1px solid var(--line); border-radius: 10px; padding: 8px; }
figure.fig img { display: block; margin: 0 auto; }
.opts { display: grid; gap: 10px; margin: 6px 0 18px; }
.opt {
  display: grid; grid-template-columns: 28px 1fr; gap: 10px; align-items: start;
  padding: 12px 14px; border: 1.5px solid var(--line); border-radius: 10px;
  background: var(--surface); cursor: pointer;
}
.opt:hover { border-color: var(--accent); }
.opt input { margin: 4px 0 0; width: 18px; height: 18px; accent-color: var(--accent); }
.opt .k { font-weight: 700; margin-right: 4px; }
.opt.sel { border-color: var(--accent); background: var(--accent-soft); }
.opt.correct { border-color: var(--ok); background: var(--ok-soft); }
.opt.wrong { border-color: var(--bad); background: var(--bad-soft); }
.opt.locked { cursor: default; }
.match { display: grid; gap: 12px; margin: 6px 0 18px; }
.match .row { padding: 12px 14px; border: 1.5px solid var(--line); border-radius: 10px; background: var(--surface); }
.match .row.correct { border-color: var(--ok); background: var(--ok-soft); }
.match .row.wrong { border-color: var(--bad); background: var(--bad-soft); }
.match .lbl { font-weight: 600; margin-bottom: 8px; display: block; }
.match select { width: 100%; min-height: 44px; font: 15px var(--font); padding: 8px; border-radius: 8px; border: 1px solid var(--line); background: var(--surface); color: var(--ink); }
.match .key { font-size: 14px; margin-top: 8px; color: var(--ok); font-weight: 600; }
.match .unused { font-size: 14px; color: var(--muted); }
.feedback { border-radius: 10px; padding: 14px 16px; margin: 0 0 16px; font-weight: 700; }
.feedback.ok { background: var(--ok-soft); color: var(--ok); }
.feedback.bad { background: var(--bad-soft); color: var(--bad); }
.rationale { border-left: 3px solid var(--accent); padding: 4px 0 4px 16px; margin: 0 0 20px; }
.rationale h4 { margin: 14px 0 4px; font-size: 14px; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); }
.rationale p { margin: 0; }
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 12px; }
.tag { font-size: 12px; padding: 2px 8px; border-radius: 99px; background: var(--surface-2); color: var(--muted); font-weight: 600; }
.bottombar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 10;
  background: var(--surface); border-top: 1px solid var(--line);
  padding: 10px 0 calc(10px + env(safe-area-inset-bottom));
}
.bottombar .wrap { display: flex; gap: 8px; justify-content: space-between; align-items: center; flex-wrap: wrap; }
.bottombar .grp { display: flex; gap: 8px; flex-wrap: wrap; }
.flagbtn.on { background: var(--flag-soft); border-color: var(--flag); color: var(--flag); }

.modal-back { position: fixed; inset: 0; background: rgba(10, 12, 16, .5); z-index: 50; display: flex; align-items: flex-end; justify-content: center; }
@media (min-width: 640px) { .modal-back { align-items: center; } }
.modal { background: var(--surface); width: 100%; max-width: 720px; max-height: 88vh; overflow: auto; border-radius: 14px 14px 0 0; padding: 20px 16px; }
@media (min-width: 640px) { .modal { border-radius: 14px; padding: 24px; } }
.modal .row-actions { display: flex; gap: 8px; justify-content: flex-end; flex-wrap: wrap; margin-top: 18px; }
.navgrid { display: grid; grid-template-columns: repeat(auto-fill, minmax(44px, 1fr)); gap: 6px; }
.navgrid button {
  min-height: 40px; border-radius: 8px; border: 1px solid var(--line); background: var(--surface);
  color: var(--ink); font: 600 14px var(--font); cursor: pointer; position: relative;
}
.navgrid button.ans { background: var(--accent-soft); border-color: var(--accent); }
.navgrid button.flag::after { content: ""; position: absolute; top: 3px; right: 3px; width: 7px; height: 7px; border-radius: 50%; background: var(--flag); }
.navgrid button.cur { outline: 2px solid var(--ink); }
.navgrid button.ok { background: var(--ok-soft); border-color: var(--ok); }
.navgrid button.ko { background: var(--bad-soft); border-color: var(--bad); }
.legend { display: flex; flex-wrap: wrap; gap: 12px; font-size: 13px; color: var(--muted); margin: 0 0 12px; }
.filters { display: flex; gap: 6px; flex-wrap: wrap; margin: 0 0 12px; }

.gate { max-width: 460px; margin: 40px auto; }
.gate input[type=text] {
  width: 100%; min-height: 48px; font: 18px var(--font); letter-spacing: .06em; text-transform: uppercase;
  padding: 10px 14px; border-radius: 10px; border: 1.5px solid var(--line); background: var(--surface); color: var(--ink);
  margin: 6px 0 12px;
}
.err { color: var(--bad); font-weight: 600; min-height: 1.4em; margin: 0 0 8px; }
.modes { display: grid; gap: 12px; margin: 18px 0; }
.mode { display: grid; grid-template-columns: 24px 1fr; gap: 10px; padding: 14px; border: 1.5px solid var(--line); border-radius: 10px; cursor: pointer; background: var(--surface); }
.mode.sel { border-color: var(--accent); background: var(--accent-soft); }
.score { font-size: 54px; font-weight: 800; line-height: 1; margin: 6px 0; font-variant-numeric: tabular-nums; }
.bars { display: grid; gap: 12px; margin: 10px 0 0; }
.bar .lab { display: flex; justify-content: space-between; font-size: 14px; margin-bottom: 4px; font-variant-numeric: tabular-nums; }
.bar .track { height: 10px; background: var(--surface-2); border-radius: 99px; overflow: hidden; }
.bar .fill { height: 100%; background: var(--accent); border-radius: 99px; }
.loading { text-align: center; padding: 60px 0; color: var(--muted); }