:root {
  color-scheme: light;
  --paper: #f2eee4;
  --surface: #fcf8ee;
  --white: var(--surface);
  --ink: #263b36;
  --muted: #697269;
  --line: #c9c9b9;
  --accent: #93473e;
  --red: var(--accent);
  --gold: #b69450;
  --green: #33554b;
  --soft: #e4e4d5;
  --wash: var(--soft);
  --shadow: #263b3624;
  --correct-bg: #e6ecdf;
  --correct-ink: #33554b;
  --wrong-bg: #f7e6df;
  --wrong-ink: #93473e;
  --unknown-bg: #f4ead3;
  --unknown-ink: #765717;
  --unknown-line: #8b6b25;
  font-family: "Yu Gothic", YuGothic, "Hiragino Kaku Gothic ProN", system-ui, sans-serif;
  font-synthesis: none;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink);
  background: var(--paper);
}
:root[data-theme=midnight] {
  color-scheme: dark;
  --paper: #202c30; --surface: #2d393a; --ink: #f1e4c9; --muted: #c4c3aa;
  --line: #6e796d; --accent: #dba38a; --gold: #d6b56f; --green: #3d5b4d;
  --soft: #344546; --shadow: #0005;
  --correct-bg: #30483d; --correct-ink: #bedbbc;
  --wrong-bg: #493733; --wrong-ink: #f0b7a0;
  --unknown-bg: #443e2f; --unknown-ink: #e1c687; --unknown-line: #d6b56f;
}
:root[data-theme=sage] {
  --paper: #dce3d2; --surface: #ebeedc; --ink: #294437; --muted: #536c57;
  --line: #a6b49d; --accent: #805244; --gold: #94733c; --green: #3c6250;
  --soft: #d0dcc7;
  --correct-bg: #d7e3cb; --correct-ink: #3c6250;
  --wrong-bg: #efdfd2; --wrong-ink: #805244;
  --unknown-bg: #eadfc0; --unknown-ink: #765717; --unknown-line: #8b6b25;
}
* { box-sizing: border-box; }
[hidden] { display: none !important; }
body { margin: 0; min-height: 100vh; border-top: 5px solid var(--accent); }
button, input, select { font: inherit; }
button, a, input, select { touch-action: manipulation; -webkit-tap-highlight-color: transparent; }
button {
  display: inline-flex; align-items: center; justify-content: center;
  min-height: 48px; padding: 10px 18px; border: 1px solid var(--ink); border-radius: 3px;
  color: var(--ink); background: var(--surface); box-shadow: 0 2px 0 var(--ink);
  font-weight: 600; line-height: 1.5; cursor: pointer;
}
button:hover:not(:disabled) { background: var(--soft); }
button:active:not(:disabled) { transform: translateY(2px); box-shadow: none; }
button:disabled { opacity: .55; cursor: not-allowed; box-shadow: none; }
a { color: inherit; text-underline-offset: 5px; }
button:focus-visible, a:focus-visible, input:focus-visible, select:focus-visible,
summary:focus-visible, [tabindex]:focus-visible { outline: 3px solid var(--gold); outline-offset: 4px; }
h1, h2, h3, h4, p { margin-top: 0; }
h1, h2, .serif { font-family: "Yu Mincho", YuMincho, "Hiragino Mincho ProN", Georgia, serif; }
h1 { font-size: clamp(28px, 4vw, 38px); line-height: 1.5; font-weight: 600; letter-spacing: .055em; margin-bottom: 14px; }
h2 { font-size: 24px; line-height: 1.5; font-weight: 600; }
h3 { font-size: 18px; line-height: 1.6; }
p { margin-bottom: 18px; }
small, .muted { color: var(--muted); }
.site-header { border-bottom: 1px solid var(--line); }
.header-inner, .footer-inner { max-width: 1180px; margin: auto; padding-inline: 34px; }
.header-inner { display: flex; align-items: center; justify-content: space-between; gap: 22px; padding-block: 22px 20px; }
.brand { display: flex; align-items: center; gap: 12px; text-decoration: none; white-space: nowrap; }
.brand-mark { width: 39px; height: 39px; display: grid; grid-template-columns: repeat(3, 1fr); gap: 3px; transform: rotate(-4deg); flex-shrink: 0; }
.brand-mark i { display: block; background: var(--accent); }
.brand-mark i:nth-child(2), .brand-mark i:nth-child(6), .brand-mark i:nth-child(7) { border-radius: 50%; background: var(--ink); }
.brand-name { font-family: "Yu Mincho", serif; font-size: 24px; font-weight: 700; letter-spacing: .11em; line-height: 1.2; }
.brand-sub { display: block; margin-top: 6px; font-family: inherit; font-size: 12px; font-weight: 400; letter-spacing: .08em; }
.header-nav { display: flex; align-items: center; flex-wrap: wrap; gap: 20px; font-size: 14px; font-weight: 600; }
.header-nav button { border: 0; background: transparent; box-shadow: none; padding: 10px 0; }
.header-nav button:hover, .header-nav a:hover { text-decoration: underline; text-underline-offset: 5px; }
.header-nav a { display: inline-flex; align-items: center; min-height: 48px; padding-block: 10px; text-decoration: none; }
.preview-note { border-bottom: 1px solid var(--line); padding: 9px 24px; text-align: center; font-size: 13px; color: var(--muted); }
main { max-width: 1040px; margin: auto; padding: 44px 34px 64px; min-height: 70vh; }
.eyebrow { display: block; margin-bottom: 12px; font: 12px ui-monospace, monospace; letter-spacing: .17em; color: var(--muted); }
.intro { max-width: 680px; margin-bottom: 32px; }
.intro p { color: var(--muted); }
.section-top { display: flex; justify-content: space-between; gap: 20px; align-items: center; margin: 32px 0 16px; }
.section-top h2 { margin: 0; }
.section-num { font: italic 24px serif; color: var(--accent); margin-right: 12px; }
.mode-grid { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 14px; }
.mode-card { position: relative; display: block; text-align: left; padding: 22px 18px; min-height: 168px; border-color: var(--line); background: var(--surface); box-shadow: 0 3px 0 var(--shadow); }
.mode-card[aria-pressed=true] { border: 2px solid var(--ink); padding: 21px 17px; background: var(--soft); }
.mode-index { font: italic 22px serif; color: var(--accent); display: block; margin-bottom: 12px; }
.mode-title { font-weight: 700; display: block; font-size: 17px; margin-bottom: 8px; }
.mode-description { display: block; color: var(--muted); font-size: 14px; font-weight: 400; line-height: 1.8; }
.panel { background: var(--surface); border: 1px solid var(--line); padding: 28px; border-radius: 3px; box-shadow: 0 5px 0 var(--shadow); min-width: 0; }
.setup { margin-top: 24px; }
.learning-controls { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 16px 24px; }
.learning-controls select { width: 100%; }
.learning-controls > .field { margin-bottom: 0; }
.learning-controls .field .field { margin-top: 16px; }
.learning-controls > .storage-note { grid-column: 1 / -1; margin: 0 0 24px; }
.selection-summary { display: block; font-size: 16px; line-height: 1.7; overflow-wrap: anywhere; }
.bank-note { font-size: 16px; color: var(--muted); margin: -10px 0 24px; }
.field { border: 0; padding: 0; margin: 0 0 24px; min-width: 0; }
.field legend, .label { font-weight: 700; font-size: 16px; margin-bottom: 12px; display: block; }
.chips { display: flex; flex-wrap: wrap; gap: 9px; }
.chip { position: relative; display: flex; align-items: center; gap: 8px; min-height: 48px; border: 1px solid var(--line); padding: 8px 14px; border-radius: 3px; cursor: pointer; font-size: 16px; background: var(--surface); }
.chip:has(input:checked) { background: var(--soft); border-color: var(--ink); }
input[type=checkbox], input[type=radio] { width: 18px; height: 18px; accent-color: var(--accent); flex-shrink: 0; }
input[type=number], select { min-height: 48px; background: var(--surface); border: 1px solid var(--line); border-radius: 3px; padding: 8px 12px; color: var(--ink); max-width: 100%; }
.count-row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.count-row input { width: 115px; }
.settings-more { border-top: 1px solid var(--line); padding-top: 16px; margin-top: 8px; }
.settings-more summary { cursor: pointer; min-height: 48px; padding: 10px 0; font-size: 16px; font-weight: 600; }
.settings-more .field { margin-top: 16px; }
.start-row { display: flex; justify-content: space-between; align-items: center; gap: 24px; border-top: 1px solid var(--line); padding-top: 24px; margin-top: 24px; }
.available { font-size: 16px; }
.available strong { font: 28px Georgia, serif; margin-right: 6px; }
.available p { margin: 4px 0 0; font-size: 14px; color: var(--muted); }
.primary { background: var(--accent); color: var(--paper); border-color: var(--accent); box-shadow: 0 2px 0 var(--accent); padding-inline: 26px; }
.primary:hover:not(:disabled) { background: var(--ink); border-color: var(--ink); color: var(--paper); box-shadow: 0 2px 0 var(--ink); }
.secondary { background: var(--surface); }
.danger { color: var(--accent); border-color: var(--accent); box-shadow: 0 2px 0 var(--accent); }
.resume { display: flex; align-items: center; gap: 24px; justify-content: space-between; background: var(--soft); border: 1px solid var(--line); border-left: 4px solid var(--correct-ink); border-radius: 3px; padding: 22px 24px; margin-bottom: 32px; }
.resume h2 { font-family: inherit; font-size: 18px; font-weight: 700; line-height: 1.6; margin-bottom: 6px; }
.resume p { font-size: 16px; margin: 0; color: var(--muted); }
.actions { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.notice { border-left: 3px solid var(--accent); padding: 12px 16px; background: var(--wrong-bg); font-size: 16px; margin-bottom: 24px; overflow-wrap: anywhere; }
.news-note { margin: 24px 0; color: var(--muted); font-size: 14px; }
.storage-note { font-size: 14px; color: var(--muted); margin: 24px 0 0; }
.workspace { max-width: 760px; margin: auto; }
.question-header { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 20px; }
.question-header p { margin: 0; font-size: 16px; }
.progress { height: 4px; background: var(--line); margin: 16px 0 28px; }
.progress span { display: block; background: var(--accent); height: 100%; }
.question-meta { font-size: 14px; color: var(--muted); display: flex; gap: 10px; flex-wrap: wrap; margin-bottom: 18px; }
.question-prompt { font-size: 23px; line-height: 1.85; font-family: inherit; font-weight: 600; white-space: pre-wrap; overflow-wrap: anywhere; margin-bottom: 26px; }
.options { display: grid; gap: 12px; }
.option { width: 100%; display: flex; justify-content: flex-start; align-items: center; text-align: left; gap: 16px; padding: 15px 18px; min-height: 60px; white-space: pre-wrap; overflow-wrap: anywhere; border-color: var(--line); box-shadow: 0 2px 0 var(--shadow); font-weight: 400; }
.option-letter { display: grid; place-items: center; width: 30px; height: 30px; flex-shrink: 0; border: 1px solid var(--line); border-radius: 50%; font: 16px Georgia, serif; }
.option[aria-pressed=true] { border: 2px solid var(--ink); background: var(--soft); padding: 14px 17px; font-weight: 600; }
.option.correct { border-color: var(--correct-ink); background: var(--correct-bg); }
.option.wrong { border-color: var(--wrong-ink); background: var(--wrong-bg); }
.question-actions { margin-top: 22px; display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.feedback { margin-top: 24px; border-top: 1px solid var(--line); padding-top: 24px; }
.feedback h3 { color: var(--accent); }
.feedback p { white-space: pre-wrap; overflow-wrap: anywhere; }
.sources { font-size: 14px; display: flex; flex-wrap: wrap; gap: 12px; color: var(--muted); }
.source-reference { min-width: 0; overflow-wrap: anywhere; flex-basis: 100%; }
.question-nav { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 24px; }
.question-nav button { padding: 8px; min-width: 48px; }
.question-nav button.answered { background: var(--soft); }
.question-nav button.current { border: 2px solid var(--ink); }
.score { font: 64px/1.2 Georgia, serif; letter-spacing: -.03em; margin: 20px 0 12px; }
.score span { font-size: 30px; color: var(--muted); }
.result-summary { border-block: 1px solid var(--line); padding: 20px 0; display: flex; gap: 30px; flex-wrap: wrap; margin: 24px 0; }
.result-summary strong { display: block; font-size: 22px; }
.result-summary small { font-size: 14px; }
.question-review { margin-top: 36px; }
.review-filters { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 12px; }
.review-filter { font-size: 16px; }
.review-filter[aria-pressed=true] { color: var(--paper); background: var(--ink); }
.review-filter-help, .review-visible-count { font-size: 14px; color: var(--muted); margin-bottom: 12px; }
.review-visible-count { margin-bottom: 20px; }
.review-list { display: grid; gap: 20px; }
.review-item { background: var(--surface); border: 1px solid var(--line); border-left: 5px solid var(--muted); border-radius: 3px; padding: 24px; box-shadow: 0 4px 0 var(--shadow); min-width: 0; }
.review-item--correct { border-left-color: var(--correct-ink); }
.review-item--wrong { border-left-color: var(--wrong-ink); }
.review-item--dontknow { border-left-color: var(--unknown-line); }
.review-item-top { display: flex; align-items: center; justify-content: space-between; gap: 14px; flex-wrap: wrap; margin-bottom: 16px; }
.review-question-number { color: var(--muted); font-size: 14px; }
.outcome-pill { display: inline-flex; align-items: center; gap: 8px; min-height: 34px; padding: 4px 12px; border: 1px solid var(--muted); border-radius: 20px; font-size: 14px; font-weight: 700; white-space: nowrap; background: var(--soft); }
.outcome-mark { font-size: 18px; line-height: 1; }
.outcome-pill--correct { color: var(--correct-ink); border-color: var(--correct-ink); background: var(--correct-bg); }
.outcome-pill--wrong { color: var(--wrong-ink); border-color: var(--wrong-ink); background: var(--wrong-bg); }
.outcome-pill--dontknow { color: var(--unknown-ink); border-color: var(--unknown-line); background: var(--unknown-bg); }
.outcome-pill--unanswered { color: var(--muted); background: var(--paper); }
.review-prompt { font-size: 18px; white-space: pre-wrap; overflow-wrap: anywhere; margin-bottom: 20px; }
.review-answers { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin-bottom: 22px; }
.review-answer { border: 1px solid var(--line); border-radius: 3px; padding: 14px 16px; background: var(--paper); min-width: 0; }
.review-answer--correct { border-color: var(--correct-ink); background: var(--correct-bg); }
.review-answer--wrong { border-color: var(--wrong-ink); background: var(--wrong-bg); }
.review-answer--dontknow { border-color: var(--unknown-line); background: var(--unknown-bg); }
.review-answer-label { display: block; font-size: 14px; font-weight: 700; margin-bottom: 8px; }
.review-answer-text { font-size: 16px; font-weight: 600; line-height: 1.8; margin: 0; white-space: pre-wrap; overflow-wrap: anywhere; }
.review-explanation { border-top: 1px solid var(--line); padding-top: 18px; }
.review-explanation h4 { font-size: 16px; margin-bottom: 10px; }
.review-explanation p { font-size: 16px; white-space: pre-wrap; overflow-wrap: anywhere; }
.history-list { display: grid; gap: 14px; margin: 24px 0; }
.history-item { display: flex; align-items: center; justify-content: space-between; gap: 20px; text-align: left; padding: 20px 24px; width: 100%; border-color: var(--line); box-shadow: 0 3px 0 var(--shadow); }
.history-item strong { display: block; margin-bottom: 4px; }
.history-item small { display: block; font-size: 14px; font-weight: 400; }
.history-score { font: 26px Georgia, serif; white-space: nowrap; }
.backup { margin-top: 36px; border-top: 1px solid var(--line); padding-top: 24px; }
.backup p { font-size: 16px; color: var(--muted); }
.empty { padding: 32px 24px; text-align: center; border: 1px dashed var(--line); border-radius: 3px; margin: 24px 0; font-size: 16px; }
.site-footer { padding: 28px 0 22px; border-top: 1px solid var(--line); color: var(--muted); }
.footer-inner { display: flex; justify-content: space-between; align-items: center; gap: 20px; font-size: 13px; flex-wrap: wrap; }
.footer-links { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.footer-links a { display: inline-flex; align-items: center; min-height: 48px; }
.app-message:empty { display: none; }
.app-message { position: fixed; bottom: 20px; left: 50%; transform: translateX(-50%); max-width: calc(100% - 32px); width: max-content; background: var(--ink); color: var(--surface); padding: 12px 20px; border-radius: 3px; z-index: 20; box-shadow: 0 4px 20px var(--shadow); font-size: 16px; pointer-events: none; }
.skip { position: absolute; left: 16px; top: -100px; background: var(--surface); padding: 12px; z-index: 30; }
.skip:focus { top: 8px; }
dialog { max-width: 520px; width: calc(100% - 32px); border: 2px solid var(--ink); border-radius: 3px; padding: 28px; background: var(--surface); color: var(--ink); box-shadow: 8px 8px 0 #0003; }
dialog::backdrop { background: #152b2877; }
dialog .actions { justify-content: flex-end; margin-top: 24px; }
dialog h2 { font-size: 22px; }
dialog p { font-size: 16px; }
.loading { padding: 35px 0; }
.quick-start { margin-bottom: 28px; }
.quick-start button { min-width: 240px; }
.quick-start .storage-note { margin-top: 12px; }
body[data-preview=false] .preview-note { display: none; }
@media (max-width: 900px) {
  .header-inner, .footer-inner { padding-inline: 24px; }
  .header-inner { flex-wrap: wrap; gap: 16px; }
  .header-nav { gap: 16px; }
  .mode-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  main { padding: 32px 24px 48px; }
  .mode-card { min-height: 156px; }
}
@media (max-width: 600px) {
  .header-inner, .footer-inner { padding-inline: 16px; }
  .header-inner { padding-block: 16px 13px; }
  .brand-name { font-size: 22px; }
  .brand-mark { width: 31px; height: 31px; }
  .brand-sub { margin-top: 4px; }
  .header-nav { justify-content: space-between; gap: 12px; width: 100%; font-size: 14px; }
  .preview-note { padding: 10px 16px; text-align: left; }
  main { padding: 28px 16px 40px; }
  .intro { margin-bottom: 24px; }
  .panel { padding: 20px 16px; }
  .learning-controls { grid-template-columns: 1fr; gap: 16px; }
  .mode-card { padding: 18px 12px; }
  .mode-card[aria-pressed=true] { padding: 17px 11px; }
  .mode-title { font-size: 16px; }
  .section-top h2 { font-size: 21px; }
  .resume { flex-direction: column; align-items: flex-start; padding: 20px; }
  .start-row { flex-direction: column; align-items: stretch; gap: 16px; }
  .start-row button, .quick-start button { width: 100%; }
  .question-header { align-items: flex-start; }
  .question-header button { padding: 10px 12px; }
  .question-prompt { font-size: 20px; }
  .option { gap: 10px; padding: 14px 12px; }
  .option[aria-pressed=true] { padding: 13px 11px; }
  .review-answers { grid-template-columns: 1fr; }
  .review-item { padding: 20px 16px; }
  .footer-inner { flex-direction: column; align-items: flex-start; gap: 12px; }
  .history-item { padding: 18px 16px; gap: 12px; }
  .history-score { font-size: 22px; }
  .actions > * { flex-grow: 1; }
  .score { font-size: 56px; }
}
.reduce-motion *, .reduce-motion *::before, .reduce-motion *::after {
  animation: none !important; transition: none !important; scroll-behavior: auto !important;
}
.question-diagram { margin: 20px 0; padding: 12px; border: 1px solid var(--line); background: var(--paper); }
.question-diagram svg { display: block; width: 100%; max-width: 480px; height: auto; margin: 0 auto; overflow: hidden; }
.question-diagram svg :is(line,circle,polygon,polyline) { fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }
.question-diagram svg text { fill: currentColor; font-size: 18px; font-family: inherit; }
.question-diagram .diagram-ink { color: var(--ink); }
.question-diagram .diagram-accent { color: var(--accent); }
.question-diagram .diagram-muted { color: var(--muted); }
.question-diagram figcaption { margin-top: 8px; font-size: 13px; color: var(--muted); line-height: 1.6; }
.diagram-description { margin-top: 8px; }
.diagram-description summary { min-height: 44px; display: flex; align-items: center; cursor: pointer; font-size: 14px; }
.diagram-description summary::before { content: '＋'; margin-right: 8px; }
.diagram-description[open] summary::before { content: '−'; }
.diagram-description p { margin-top: 0; }
.reduce-motion button:active:not(:disabled) { transform: none; }
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; scroll-behavior: auto !important; }
}