:root {
  --bg: #f6f4ee;
  --card: #ffffff;
  --ink: #1b1f2a;
  --muted: #5d6472;
  --line: #e3e0d7;
  --brand: #0b3d91;
  --brand-ink: #ffffff;
  --gold: #f2b134;
  --good: #1a7f4b;
  --good-bg: #e6f5ec;
  --bad: #c0392b;
  --bad-bg: #fbe9e7;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(20, 24, 40, .06), 0 8px 24px rgba(20, 24, 40, .06);
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12151c;
    --card: #1b2029;
    --ink: #eef0f4;
    --muted: #9aa3b2;
    --line: #2b3240;
    --brand: #6b9bff;
    --brand-ink: #0b1220;
    --good: #4cc38a;
    --good-bg: #163527;
    --bad: #ff8577;
    --bad-bg: #3b1f1b;
    --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px rgba(0, 0, 0, .25);
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 17px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
a { color: var(--brand); }
h1, h2, h3 { line-height: 1.2; margin: 0 0 .5rem; letter-spacing: -.01em; }
h1 { font-size: 1.9rem; }
h2 { font-size: 1.2rem; margin-top: 1.6rem; }
p { margin: 0 0 1rem; }
ul { padding-left: 1.2rem; margin: 0 0 1rem; }
li { margin: .35rem 0; }
strong { color: var(--brand); }
@media (prefers-color-scheme: dark) { strong { color: var(--gold); } }

.top {
  position: sticky; top: 0; z-index: 5;
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
  padding: .7rem 1rem;
  background: var(--brand); color: var(--brand-ink);
}
.top a { color: inherit; text-decoration: none; font-weight: 600; }
.brand { font-size: 1.05rem; display: flex; align-items: center; gap: .4rem; }
.logo { font-size: 1.3rem; }
.top nav { display: flex; gap: 1rem; align-items: center; font-size: .95rem; }
.pill { background: var(--gold); color: #1b1f2a !important; padding: .35rem .8rem; border-radius: 999px; }

#app { max-width: 760px; margin: 0 auto; padding: 1.25rem 1rem 3rem; }
.foot { max-width: 760px; margin: 0 auto; padding: 1rem 1rem 2.5rem; color: var(--muted); font-size: .85rem; }

.btn {
  display: inline-block; cursor: pointer;
  border: 1.5px solid var(--brand); border-radius: 10px;
  background: var(--card); color: var(--brand);
  padding: .6rem 1.1rem; font: inherit; font-weight: 600; text-decoration: none;
  min-height: 44px;
}
.btn.primary { background: var(--brand); color: var(--brand-ink); }
.btn.big { padding: .9rem 1.4rem; font-size: 1.05rem; width: 100%; text-align: center; }
.btn:disabled { opacity: .5; cursor: default; }
.actions { display: flex; flex-wrap: wrap; gap: .6rem; margin-top: 1rem; }
.back { display: inline-block; margin-bottom: .8rem; text-decoration: none; font-weight: 600; }
.kicker { color: var(--muted); font-size: .85rem; text-transform: uppercase; letter-spacing: .06em; font-weight: 600; }
.muted { color: var(--muted); }

.hero { margin-bottom: 1.5rem; }
.hero p { color: var(--muted); font-size: 1.05rem; }
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: .6rem; margin: 1rem 0; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: .7rem .8rem; }
.stat b { display: block; font-size: 1.35rem; line-height: 1.2; }
.stat span { color: var(--muted); font-size: .8rem; }
.banner {
  background: var(--card); border-left: 5px solid var(--gold); border-radius: 10px;
  padding: .8rem 1rem; margin: 1rem 0; box-shadow: var(--shadow);
}
.banner.ready { border-left-color: var(--good); }

.sections { list-style: none; padding: 0; margin: 0; display: grid; gap: .8rem; }
@media (min-width: 720px) { .sections { grid-template-columns: 1fr 1fr; } }
.card {
  display: block; text-decoration: none; color: inherit;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1rem; box-shadow: var(--shadow);
  transition: transform .12s ease, border-color .12s ease;
}
.card:hover { transform: translateY(-2px); border-color: var(--brand); }
.card.done { border-color: var(--good); }
.card .num { color: var(--muted); font-size: .8rem; font-weight: 700; }
.card h3 { font-size: 1.05rem; margin: .15rem 0 .35rem; }
.card p { color: var(--muted); font-size: .9rem; margin-bottom: .7rem; }
.meta { display: flex; justify-content: space-between; align-items: center; gap: .5rem; font-size: .8rem; color: var(--muted); }
.bar { height: 6px; background: var(--line); border-radius: 999px; overflow: hidden; margin-top: .5rem; }
.bar i { display: block; height: 100%; background: var(--good); width: 0; transition: width .3s ease; }
.bar.brand i { background: var(--brand); }
.tag { font-weight: 700; }
.tag.good { color: var(--good); }

.sec-head { margin-bottom: .5rem; }
.lesson ul li::marker { color: var(--brand); }
table.numbers { width: 100%; border-collapse: collapse; margin-bottom: 1rem; background: var(--card); border-radius: 10px; overflow: hidden; border: 1px solid var(--line); }
table.numbers th { text-align: left; white-space: nowrap; padding: .55rem .8rem; color: var(--brand); font-size: 1rem; border-bottom: 1px solid var(--line); width: 1%; }
table.numbers td { padding: .55rem .8rem; border-bottom: 1px solid var(--line); font-size: .95rem; }
table.numbers tr:last-child th, table.numbers tr:last-child td { border-bottom: 0; }
@media (prefers-color-scheme: dark) { table.numbers th { color: var(--gold); } }
.cta { position: sticky; bottom: 0; padding: .8rem 0 .4rem; background: linear-gradient(to top, var(--bg) 70%, transparent); }

.quiz .progress { display: flex; justify-content: space-between; font-size: .85rem; color: var(--muted); margin: .2rem 0 .4rem; }
.question {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 1.1rem 1.2rem; margin: .8rem 0 1rem; font-size: 1.15rem; font-weight: 600; line-height: 1.4; box-shadow: var(--shadow);
}
.choices { display: grid; gap: .6rem; }
.choice {
  display: flex; align-items: center; gap: .8rem; width: 100%; text-align: left;
  background: var(--card); color: var(--ink); border: 1.5px solid var(--line); border-radius: 12px;
  padding: .8rem .9rem; font: inherit; cursor: pointer; min-height: 52px;
  transition: border-color .1s ease, background .1s ease;
}
.choice:hover:not(:disabled) { border-color: var(--brand); }
.choice:disabled { cursor: default; }
.choice .letter {
  flex: none; width: 30px; height: 30px; border-radius: 50%;
  display: grid; place-items: center; font-weight: 700; font-size: .85rem;
  background: var(--bg); border: 1px solid var(--line);
}
.choice.correct { border-color: var(--good); background: var(--good-bg); }
.choice.correct .letter { background: var(--good); color: #fff; border-color: var(--good); }
.choice.wrong { border-color: var(--bad); background: var(--bad-bg); }
.choice.wrong .letter { background: var(--bad); color: #fff; border-color: var(--bad); }
.feedback { border-radius: 12px; padding: .9rem 1rem; margin-top: 1rem; border: 1.5px solid; }
.feedback.ok { border-color: var(--good); background: var(--good-bg); }
.feedback.no { border-color: var(--bad); background: var(--bad-bg); }
.feedback b { display: block; margin-bottom: .3rem; }
.feedback p { margin: 0 0 .8rem; }
.hint { color: var(--muted); font-size: .8rem; margin-top: 1rem; }

.result { text-align: center; padding: 1.5rem 0 .5rem; }
.score { font-size: 3.2rem; font-weight: 800; line-height: 1; letter-spacing: -.02em; }
.score.pass { color: var(--good); }
.score.fail { color: var(--bad); }
.verdict { font-size: 1.2rem; font-weight: 700; margin: .4rem 0 .2rem; }
.breakdown { width: 100%; border-collapse: collapse; margin: 1rem 0; font-size: .95rem; }
.breakdown td { padding: .4rem .3rem; border-bottom: 1px solid var(--line); }
.breakdown td:last-child { text-align: right; white-space: nowrap; font-weight: 600; }
.missed { list-style: none; padding: 0; margin: 1rem 0; display: grid; gap: .7rem; }
.missed li { background: var(--card); border: 1px solid var(--line); border-left: 4px solid var(--bad); border-radius: 10px; padding: .8rem 1rem; }
.missed .q { font-weight: 600; }
.missed .ans { color: var(--good); font-weight: 600; }
.missed .why { color: var(--muted); font-size: .92rem; margin: .2rem 0 0; }

.option { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 1rem; margin: 1rem 0; box-shadow: var(--shadow); }
.option h3 { margin: 0 0 .3rem; }
.option p { color: var(--muted); font-size: .92rem; }
.danger { color: var(--bad); background: none; border: 0; font: inherit; font-size: .85rem; cursor: pointer; text-decoration: underline; padding: 0; }
.empty { text-align: center; padding: 2rem 0; color: var(--muted); }

/* ---------- touch & small screens ---------- */
a, button { touch-action: manipulation; -webkit-tap-highlight-color: transparent; }
.top { padding-top: calc(.7rem + env(safe-area-inset-top)); }
#app { padding-bottom: calc(3rem + env(safe-area-inset-bottom)); }
.cta { padding-bottom: calc(.4rem + env(safe-area-inset-bottom)); }
@media (max-width: 600px) {
  body { font-size: 16px; }
  h1 { font-size: 1.55rem; }
  .hero p { font-size: .98rem; }
  .stats { gap: .4rem; }
  .stat { padding: .55rem .6rem; }
  .stat b { font-size: 1.15rem; }
  .stat span { font-size: .72rem; }
  .actions .btn { flex: 1 1 100%; text-align: center; }
  .card:hover { transform: none; }
  .question { font-size: 1.08rem; padding: .95rem 1rem; }
  .choice { padding: .85rem .8rem; min-height: 56px; font-size: 1rem; }
  .feedback .btn { display: block; width: 100%; text-align: center; padding: .85rem 1rem; }
  .breakdown td:first-child { max-width: 60vw; }
  .hint { display: none; }
}
@media (hover: none) { .card:hover { transform: none; border-color: var(--line); } }