*, *::before, *::after { box-sizing: border-box; }

:root {
  --bg: #f6f7f9;
  --card: #ffffff;
  --fg: #1b1f24;
  --muted: #5b6472;
  --line: #dde1e6;
  --accent: #1d3557;
  --accent-fg: #ffffff;
  --right-bg: #e7f6ec;
  --right-edge: #1a7f43;
  --right-fg: #10532c;
  --wrong-bg: #fdecec;
  --wrong-edge: #c0392b;
  --wrong-fg: #8f2318;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14181d;
    --card: #1c2229;
    --fg: #eef1f4;
    --muted: #a2acba;
    --line: #2e3742;
    --accent: #6ea8fe;
    --accent-fg: #10202f;
    --right-bg: #14301f;
    --right-edge: #3fb56b;
    --right-fg: #b7e9c8;
    --wrong-bg: #331b1b;
    --wrong-edge: #e06b5c;
    --wrong-fg: #f6c6bf;
  }
}

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

body {
  margin: 0;
  padding: 0 1rem calc(2rem + env(safe-area-inset-bottom));
  background: var(--bg);
  color: var(--fg);
  font: 1rem/1.55 system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

.site-header {
  max-width: 34rem;
  margin: 0 auto;
  padding: calc(1rem + env(safe-area-inset-top)) 0 .5rem;
}

.site-title {
  margin: 0;
  font-size: .8rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--muted);
}

main {
  max-width: 34rem;
  margin: 0 auto;
}

h1 { font-size: 1.5rem; line-height: 1.25; margin: 0 0 .5rem; }
h2 { font-size: 1.2rem; line-height: 1.35; margin: 0 0 .75rem; }
p { margin: 0 0 1rem; }

.hint, .sub { color: var(--muted); }
.sub { margin: 0 0 1rem; }
.perfect { text-align: center; }

.cat {
  margin: 0 0 .5rem;
  font-size: .75rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--muted);
}

.q { margin: 0 0 1.25rem; font-size: 1.2rem; }

.score {
  margin: 0 0 .25rem;
  font-size: 2.75rem;
  font-weight: 700;
  line-height: 1;
}

/* CARD */

.card {
  padding: 1.25rem;
  margin-bottom: 1rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: .75rem;
}

/* PROGRESS */

.progress { margin-bottom: .75rem; }
.count { margin: 0 0 .35rem; font-size: .85rem; color: var(--muted); }

.bar {
  display: block;
  width: 100%;
  height: .4rem;
  appearance: none;
  border: 0;
  border-radius: 1rem;
  background: var(--line);
}

.bar::-webkit-progress-bar { background: var(--line); border-radius: 1rem; }
.bar::-webkit-progress-value { background: var(--accent); border-radius: 1rem; }
.bar::-moz-progress-bar { background: var(--accent); border-radius: 1rem; }

/* OPTIONS */

.options { display: grid; gap: .5rem; }

.option {
  display: flex;
  gap: .7rem;
  align-items: flex-start;
  width: 100%;
  min-height: 3rem;
  padding: .7rem .8rem;
  font: inherit;
  text-align: left;
  color: var(--fg);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: .6rem;
  cursor: pointer;
}

.option:not(:disabled):hover { border-color: var(--accent); }
.option:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.option:disabled { cursor: default; }

.letter {
  flex: none;
  font-weight: 700;
  color: var(--muted);
}

.option-right {
  background: var(--right-bg);
  border-color: var(--right-edge);
  color: var(--right-fg);
}

.option-wrong {
  background: var(--wrong-bg);
  border-color: var(--wrong-edge);
  color: var(--wrong-fg);
}

.option-faded { opacity: .5; }
.option-right .letter, .option-wrong .letter { color: inherit; }

/* FEEDBACK */

.feedback {
  margin-top: 1.25rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
}

.verdict { margin: 0 0 .5rem; font-weight: 700; }
.feedback-right .verdict { color: var(--right-edge); }
.feedback-wrong .verdict { color: var(--wrong-edge); }
.why { margin: 0 0 1rem; font-size: .95rem; }

/* BUTTONS */

.btn {
  display: block;
  width: 100%;
  min-height: 3rem;
  padding: .75rem 1rem;
  font: inherit;
  font-weight: 600;
  color: var(--accent-fg);
  background: var(--accent);
  border: 0;
  border-radius: .6rem;
  cursor: pointer;
}

.btn:focus-visible { outline: 2px solid var(--fg); outline-offset: 2px; }

.lengths { margin: 0 0 1.25rem; padding: 0; border: 0; }
.lengths legend { padding: 0 0 .5rem; font-size: .85rem; color: var(--muted); }
.length-row { display: flex; flex-wrap: wrap; gap: .5rem; }

.length {
  flex: 1 1 4.5rem;
  min-height: 2.75rem;
  padding: .5rem;
  font: inherit;
  color: var(--fg);
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: .6rem;
  cursor: pointer;
}

.length-on { background: var(--accent); border-color: var(--accent); color: var(--accent-fg); font-weight: 600; }
.length:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

/* REVIEW */

.review h2 { margin: 1.5rem 0 .75rem; }

.miss {
  padding: .85rem 1rem;
  margin-bottom: .5rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: .6rem;
}

.miss summary { font-weight: 600; cursor: pointer; }
.miss summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.miss p { margin: .75rem 0 0; }
.miss .cat { margin: .75rem 0 0; }

.error {
  margin: 0 0 1rem;
  padding: .75rem;
  overflow-x: auto;
  font-size: .8rem;
  background: var(--wrong-bg);
  border-radius: .5rem;
  color: var(--wrong-fg);
}

.test-note {
  margin: 1rem 0 0;
  padding: .75rem .875rem;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: .5rem;
  font-size: .9rem;
  color: var(--muted);
}

.result-pass { color: var(--right-fg); }
.result-fail { color: var(--wrong-fg); }

.exit {
  display: block;
  margin: 0 0 .75rem;
  padding: .375rem .5rem .375rem 0;
  background: none;
  border: 0;
  color: var(--muted);
  font-size: .85rem;
  text-decoration: underline;
  text-underline-offset: 2px;
  cursor: pointer;
}

.exit-confirm {
  margin: 0 0 .75rem;
  padding: .75rem .875rem;
  background: var(--wrong-bg);
  border: 1px solid var(--wrong-edge);
  border-radius: .5rem;
}

.exit-confirm p {
  margin: 0 0 .625rem;
  font-size: .9rem;
  color: var(--wrong-fg);
}

.exit-actions {
  display: flex;
  gap: .5rem;
  flex-wrap: wrap;
}

.btn-quiet,
.btn-danger {
  flex: 1 1 8rem;
  min-height: 44px;
  padding: .5rem .875rem;
  font: inherit;
  font-size: .9rem;
  font-weight: 600;
  border-radius: .5rem;
  cursor: pointer;
}

.btn-quiet {
  background: var(--card);
  border: 1px solid var(--line);
  color: var(--fg);
}

.btn-danger {
  background: var(--wrong-edge);
  border: 1px solid var(--wrong-edge);
  color: #fff;
}

.exit:focus-visible,
.btn-quiet:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.btn-danger:focus-visible {
  outline: 2px solid var(--fg);
  outline-offset: 2px;
}