:root {
  color-scheme: dark;
  --bg: #0d1018;
  --bg-soft: #141927;
  --surface: rgba(25, 31, 47, 0.88);
  --surface-strong: #1d2435;
  --surface-hover: #252e43;
  --text: #f7f8fc;
  --muted: #aab2c6;
  --faint: #747f98;
  --border: rgba(187, 200, 232, 0.16);
  --border-strong: rgba(187, 200, 232, 0.3);
  --accent: #8492ff;
  --accent-2: #4bd2b1;
  --danger: #ff7d93;
  --warning: #ffc86f;
  --success: #62d9b2;
  --shadow: none;
  --radius-xl: 12px;
  --radius-lg: 10px;
  --radius-md: 8px;
  --radius-sm: 6px;
  --content: 1120px;
  --reading: 760px;
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    color-scheme: light;
    --bg: #f4f6fb;
    --bg-soft: #e9edf7;
    --surface: rgba(255, 255, 255, 0.9);
    --surface-strong: #ffffff;
    --surface-hover: #f1f4fb;
    --text: #141824;
    --muted: #566077;
    --faint: #7e8799;
    --border: rgba(35, 46, 74, 0.12);
    --border-strong: rgba(35, 46, 74, 0.24);
    --shadow: none;
  }
}

* { box-sizing: border-box; }
html { min-height: 100%; scroll-behavior: smooth; }
body {
  min-height: 100vh;
  margin: 0;
  color: var(--text);
  background: var(--bg);
}
button, input, select { font: inherit; }
button { color: inherit; }
a { color: var(--accent); }

.app-shell { min-height: 100vh; }
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}
.header-inner {
  max-width: var(--content);
  min-height: 58px;
  margin: 0 auto;
  padding: 0 22px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}
.brand {
  font-weight: 800;
  letter-spacing: -0.02em;
  font-size: 1rem;
  white-space: nowrap;
}
.header-actions { display: flex; align-items: center; gap: 4px; overflow-x: auto; }
.file-links { display: flex; flex-wrap: wrap; gap: 8px; margin: 18px 0; }

.main { max-width: var(--content); margin: 0 auto; padding: 32px 22px 64px; }
.reading { max-width: var(--reading); margin: 0 auto; }

h1, h2, h3, p { margin-top: 0; }
h2 { font-size: clamp(1.65rem, 3vw, 2.15rem); line-height: 1.12; letter-spacing: -0.025em; }
h3 { font-size: 1.08rem; letter-spacing: -0.01em; }
.eyebrow {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 750;
  margin-bottom: 10px;
}


.card {
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  background: var(--surface);
  box-shadow: none;
  padding: clamp(22px, 4vw, 34px);
}
.card + .card { margin-top: 20px; }
.card-subtle { box-shadow: none; background: color-mix(in srgb, var(--surface) 72%, transparent); }
.section-head { margin-bottom: 28px; }
.section-head p { color: var(--muted); line-height: 1.6; margin-bottom: 0; }

.btn {
  appearance: none;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--surface-strong);
  color: var(--text);
  padding: 11px 16px;
  min-height: 44px;
  cursor: pointer;
  font-weight: 720;
  transition: border-color 120ms ease, background 120ms ease, opacity 120ms ease;
}
.btn:hover { border-color: var(--accent); background: var(--surface-hover); }
.btn:focus-visible, .choice:focus-visible, .answer-btn:focus-visible, select:focus-visible, input:focus-visible { outline: 3px solid color-mix(in srgb, var(--accent) 45%, transparent); outline-offset: 2px; }
.btn:disabled { opacity: 0.42; cursor: not-allowed; transform: none; }
.btn-primary {
  border-color: var(--accent);
  background: var(--accent);
  color: #0d1018;
}
.btn-primary:hover { background: color-mix(in srgb, var(--accent) 88%, white); }
.btn-ghost { background: transparent; border-color: transparent; color: var(--muted); }
.btn-danger { color: var(--danger); }
.btn-small { min-height: 34px; padding: 6px 9px; font-size: 0.84rem; }
.icon-btn { width: 38px; padding: 0; display: grid; place-items: center; }

.stepper { display: flex; gap: 6px; margin-bottom: 16px; }
.step-dot { height: 3px; flex: 1; background: var(--border); }
.step-dot.active { background: var(--accent); }

.choice-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 8px; }
.choice-grid.compact { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.choice {
  appearance: none;
  text-align: left;
  border: 1px solid var(--border);
  background: var(--surface-strong);
  color: var(--text);
  border-radius: 8px;
  padding: 14px 15px;
  min-height: 54px;
  cursor: pointer;
  transition: border-color 120ms ease, background 120ms ease;
}
.choice:hover { border-color: var(--accent); background: var(--surface-hover); }
.choice.selected { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 14%, var(--surface-strong)); box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--accent) 60%, transparent); }
.choice small { display: block; color: var(--muted); margin-top: 4px; line-height: 1.35; }

.form-row { display: grid; gap: 8px; margin-top: 20px; }
.form-row label { color: var(--muted); font-size: 0.9rem; font-weight: 700; }
select, input[type="search"] {
  width: 100%;
  min-height: 48px;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background: var(--surface-strong);
  color: var(--text);
  padding: 10px 13px;
}
.option-hint { color: var(--faint); font-size: 0.9rem; margin-top: 10px; }
.actions-row { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-top: 30px; }
.actions-row.end { justify-content: flex-end; }

.route-summary { display: grid; gap: 12px; margin: 20px 0; }
.route-line { display: flex; justify-content: space-between; gap: 20px; padding: 14px 0; border-bottom: 1px solid var(--border); }
.route-line span:first-child { color: var(--muted); }
.route-line strong { text-align: right; }
.length-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 22px; }
.length-card { min-height: 132px; }

.quiz-wrap { max-width: 900px; margin: 0 auto; }
.quiz-top { display: grid; gap: 12px; margin-bottom: 18px; }
.progress-meta { display: flex; justify-content: space-between; color: var(--muted); font-size: 0.9rem; }
.progress-track { height: 8px; background: var(--border); border-radius: 999px; overflow: hidden; }
.progress-bar { height: 100%; width: 0; background: var(--accent); border-radius: inherit; transition: width 160ms ease; }
.question-card { min-height: 480px; display: grid; align-content: center; }
.question-number { color: var(--accent-2); font-weight: 760; margin-bottom: 14px; }
.question-text { font-size: clamp(1.55rem, 3.2vw, 2.55rem); line-height: 1.18; letter-spacing: -0.035em; margin-bottom: 30px; }
.answer-grid { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 9px; }
.answer-btn {
  appearance: none;
  min-height: 84px;
  padding: 12px 8px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface-strong);
  color: var(--text);
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 710;
  line-height: 1.25;
  transition: border-color 120ms ease, background 120ms ease;
}
.answer-btn:hover { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 10%, var(--surface-strong)); }
.answer-key { display: block; color: var(--faint); font-size: 0.76rem; margin-top: 8px; }
.quiz-footer { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-top: 14px; }
.source-details { color: var(--muted); font-size: 0.9rem; }
.source-details summary { cursor: pointer; }
.source-box { margin-top: 8px; padding: 12px; border-radius: 10px; background: var(--bg-soft); }

.results-header { display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: start; }
.result-kicker { color: var(--accent-2); font-weight: 800; margin-bottom: 8px; }
.result-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.axis-group { margin-top: 30px; }
.axis-group:first-child { margin-top: 24px; }
.axis-group > h3 { margin: 0 0 12px; color: var(--muted); font-size: 0.9rem; letter-spacing: 0.08em; text-transform: uppercase; }
.axis-list { display: grid; gap: 18px; margin-top: 0; }
.axis-row { display: grid; gap: 8px; }
.axis-meta { display: flex; justify-content: space-between; gap: 14px; font-size: 0.92rem; }
.axis-meta span { max-width: 46%; }
.axis-meta span:last-child { text-align: right; }
.axis-track { height: 22px; position: relative; border-radius: 999px; overflow: hidden; background: linear-gradient(90deg, color-mix(in srgb, var(--accent-2) 38%, var(--surface-strong)), color-mix(in srgb, var(--accent) 38%, var(--surface-strong))); border: 1px solid var(--border); }
.axis-marker { position: absolute; top: 2px; bottom: 2px; width: 6px; border-radius: 999px; background: var(--text); box-shadow: 0 0 0 2px color-mix(in srgb, var(--bg) 70%, transparent); transform: translateX(-50%); }
.axis-score { color: var(--muted); font-size: 0.83rem; text-align: center; }

.indicator-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 10px; }
.indicator-item { display: grid; gap: 5px; min-height: 104px; padding: 15px; border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--surface-strong); }
.indicator-item span { color: var(--muted); font-size: 0.8rem; font-weight: 800; letter-spacing: 0.06em; text-transform: uppercase; }
.indicator-item strong { line-height: 1.25; }
.indicator-item small { color: var(--faint); }

.match-grid { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 12px; margin-top: 18px; }
.match-card { border: 1px solid var(--border); background: var(--surface-strong); border-radius: var(--radius-lg); padding: 18px; }
.match-rank { color: var(--accent-2); font-weight: 800; font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.06em; }
.match-name { margin: 8px 0 6px; font-size: 1.16rem; }
.match-card p { color: var(--muted); line-height: 1.45; font-size: 0.9rem; margin-bottom: 12px; }
.similarity { font-weight: 850; }

.tag-list { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }
.tag { display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--border); border-radius: 999px; padding: 8px 11px; background: var(--surface-strong); font-size: 0.88rem; }
.tag strong { color: var(--accent-2); }

.calibration { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.calibration-box { padding: 18px; background: var(--surface-strong); border: 1px solid var(--border); border-radius: var(--radius-lg); }
.calibration-box p { color: var(--muted); margin-bottom: 0; line-height: 1.5; }

.method-grid { display: grid; grid-template-columns: 0.8fr 1.2fr; gap: 18px; align-items: start; }
.method-nav { position: sticky; top: 92px; display: grid; gap: 8px; }
.method-nav .btn { text-align: left; }
.method-content { display: grid; gap: 18px; }
.method-content p, .method-content li { color: var(--muted); line-height: 1.65; }
.code-box { overflow: auto; padding: 15px; background: #080a10; color: #dce3f5; border-radius: 12px; border: 1px solid var(--border); font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 0.86rem; line-height: 1.55; }
.axis-definition { padding: 16px 0; border-bottom: 1px solid var(--border); }
.axis-definition:last-child { border-bottom: 0; }
.question-bank { max-height: 620px; overflow: auto; border: 1px solid var(--border); border-radius: var(--radius-lg); background: var(--surface-strong); }
.question-item { padding: 14px 16px; border-bottom: 1px solid var(--border); }
.question-item:last-child { border-bottom: 0; }
.question-item code { color: var(--accent-2); font-size: 0.78rem; }
.question-item p { margin: 5px 0 0; color: var(--text); }
.question-item small { display: block; margin-top: 6px; color: var(--faint); }

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translate(-50%, 18px);
  opacity: 0;
  pointer-events: none;
  z-index: 50;
  max-width: calc(100vw - 32px);
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  background: var(--surface-strong);
  color: var(--text);
  box-shadow: var(--shadow);
  padding: 12px 16px;
  transition: opacity 160ms ease, transform 160ms ease;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

.notice { padding: 14px 16px; border: 1px solid var(--border); border-radius: 12px; background: var(--bg-soft); color: var(--muted); line-height: 1.5; }
.notice.warning { border-color: color-mix(in srgb, var(--warning) 45%, var(--border)); }
.notice.danger { border-color: color-mix(in srgb, var(--danger) 45%, var(--border)); }
.muted { color: var(--muted); }
.faint { color: var(--faint); }
.hidden { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; }
.noscript-card { max-width: 680px; margin: 80px auto; padding: 32px; border: 1px solid var(--border); border-radius: 20px; background: var(--surface); }

@media (max-width: 900px) {
  .method-grid { grid-template-columns: 1fr; }
  .method-nav { position: static; grid-template-columns: repeat(2, minmax(0,1fr)); }
  .match-grid { grid-template-columns: 1fr; }
  .indicator-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .results-header { grid-template-columns: 1fr; }
  .result-actions { justify-content: flex-start; }
}

@media (max-width: 680px) {
  .main { padding: 32px 14px 60px; }
  .header-inner { padding: 0 10px; gap: 10px; }
  .header-actions { gap: 2px; }
  .btn-small { padding: 6px 7px; font-size: 0.78rem; }
  .choice-grid, .choice-grid.compact, .length-grid, .calibration { grid-template-columns: 1fr; }
  .card { border-radius: 10px; padding: 20px 16px; }
  .answer-grid { grid-template-columns: 1fr; }
  .answer-btn { min-height: 56px; display: flex; align-items: center; justify-content: space-between; padding: 12px 14px; text-align: left; }
  .answer-key { display: inline; margin: 0 0 0 8px; }
  .question-card { min-height: auto; align-content: start; }
  .question-text { font-size: 1.55rem; }
  .quiz-footer, .actions-row { align-items: stretch; }
  .quiz-footer { flex-direction: column-reverse; }
  .actions-row .btn, .quiz-footer .btn { flex: 1; }
  .axis-meta { font-size: 0.78rem; }
  .method-nav { grid-template-columns: 1fr 1fr; }
  .indicator-grid { grid-template-columns: 1fr; }
}

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