:root {
  color-scheme: light;
  --bg: #f6f7f2;
  --surface: #ffffff;
  --surface-soft: #edf2e8;
  --ink: #18211d;
  --muted: #5d675f;
  --line: #dce2d8;
  --primary: #0f6f5c;
  --primary-dark: #0a4d42;
  --accent: #d45d2c;
  --code-bg: #17211f;
  --code-ink: #e9f3ed;
  --radius: 8px;
  --shadow: 0 18px 40px rgba(24, 33, 29, 0.1);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.7;
}

a {
  color: inherit;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px clamp(16px, 4vw, 44px);
  background: rgba(246, 247, 242, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  border-radius: var(--radius);
  background: var(--primary);
  color: white;
  font-weight: 800;
  font-size: 0.86rem;
}

.brand strong,
.brand small {
  display: block;
}

.brand strong {
  font-size: calc(1rem - 1pt);
  line-height: 1.15;
}

.brand small {
  color: var(--muted);
  font-size: 0.76rem;
}

.nav {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
  justify-content: flex-end;
}

.nav a,
.filters a {
  min-height: 40px;
  padding: 8px 12px;
  border-radius: var(--radius);
  color: var(--muted);
  text-decoration: none;
  font-weight: 700;
}

.nav a:hover,
.filters a:hover,
.filters a.active {
  background: var(--surface-soft);
  color: var(--primary-dark);
}

.app {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 36px 0 54px;
  outline: none;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 24px;
  align-items: stretch;
  min-height: 420px;
  padding: clamp(28px, 6vw, 64px);
  border-radius: var(--radius);
  background:
    linear-gradient(135deg, rgba(15, 111, 92, 0.95), rgba(24, 33, 29, 0.88)),
    repeating-linear-gradient(90deg, rgba(255,255,255,0.12) 0 1px, transparent 1px 24px);
  color: white;
  box-shadow: var(--shadow);
}

.hero h1,
.page-title h1 {
  margin: 0;
  font-size: clamp(2.1rem, 5vw, 4.05rem);
  line-height: 1.05;
  letter-spacing: 0;
  overflow-wrap: normal;
  word-break: keep-all;
}

.hero-title {
  margin: 0;
  max-width: 100%;
  font-size: clamp(1.9rem, 4.4vw, 3.35rem);
  line-height: 1.08;
  letter-spacing: 0;
  overflow-wrap: normal;
  word-break: keep-all;
}

.hero-title-main,
.hero-title-tail {
  display: inline-block;
  white-space: nowrap;
}

.hero p,
.page-title p,
.split p {
  max-width: 720px;
  color: inherit;
  font-size: 1.05rem;
}

.no-break {
  white-space: nowrap;
}

.hero-copy {
  align-self: center;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

.hero .eyebrow {
  color: #ffd3b2;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 28px;
}

.button,
.retry-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 12px 18px;
  border: 1px solid transparent;
  border-radius: var(--radius);
  font: inherit;
  font-weight: 800;
  text-decoration: none;
  cursor: pointer;
}

.primary,
.retry-button {
  background: var(--accent);
  color: white;
}

.secondary {
  border-color: rgba(255, 255, 255, 0.5);
  color: white;
}

.hero-panel {
  display: grid;
  align-content: center;
  gap: 6px;
  padding: 24px;
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: var(--radius);
  background: rgba(255, 255, 255, 0.12);
}

.hero-panel strong {
  font-size: 4rem;
  line-height: 1;
}

.hero-panel span {
  font-size: 1.15rem;
  font-weight: 800;
}

.hero-panel small {
  color: rgba(255, 255, 255, 0.82);
}

.notice,
.section,
.page-title,
.info-grid article,
.question-row,
.question-detail,
.filters {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.notice {
  margin-top: 22px;
  padding: 16px 18px;
  color: var(--muted);
  font-size: 0.92rem;
}

.section,
.page-title {
  margin-top: 24px;
  padding: clamp(22px, 4vw, 34px);
}

.section-heading h2,
.section h2,
.choices h2,
.answer-box h2,
.info-grid h2 {
  margin: 0 0 12px;
  font-size: clamp(1.3rem, 3vw, 2rem);
  line-height: 1.25;
  letter-spacing: 0;
}

.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 12px;
  padding: 0;
  margin: 18px 0 0;
  list-style: none;
}

.category-grid a {
  display: flex;
  min-height: 78px;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-soft);
  text-decoration: none;
  font-weight: 800;
}

.category-grid span {
  color: var(--primary);
  white-space: nowrap;
}

.split {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.split .primary {
  flex: 0 0 auto;
}

.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 14px;
  margin-top: 24px;
}

.info-grid article {
  padding: 22px;
}

.filters {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
  margin-top: 20px;
  padding: 10px;
}

.question-list {
  display: grid;
  gap: 10px;
  margin-top: 18px;
}

.question-row {
  display: grid;
  grid-template-columns: 190px minmax(0, 1fr) 80px;
  gap: 14px;
  align-items: center;
  padding: 16px;
  text-decoration: none;
}

.question-row:hover {
  border-color: rgba(15, 111, 92, 0.5);
  box-shadow: 0 10px 24px rgba(24, 33, 29, 0.08);
}

.badge,
.difficulty {
  display: inline-flex;
  width: fit-content;
  align-items: center;
  min-height: 30px;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--surface-soft);
  color: var(--primary-dark);
  font-size: 0.82rem;
  font-weight: 800;
  white-space: nowrap;
}

.question-detail {
  padding: clamp(20px, 4vw, 34px);
}

.question-head {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.question-head h1,
.question-head p {
  flex-basis: 100%;
}

.question-head h1 {
  margin: 10px 0 0;
  font-size: clamp(1.7rem, 5vw, 3rem);
  line-height: 1.18;
  letter-spacing: 0;
}

.back-link {
  color: var(--primary-dark);
  font-weight: 800;
}

.code-block {
  overflow-x: auto;
  margin: 24px 0;
  padding: 18px;
  border-radius: var(--radius);
  background: var(--code-bg);
  color: var(--code-ink);
  font-size: clamp(0.88rem, 2.8vw, 1rem);
  line-height: 1.6;
}

.code-block code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

.choices ol,
.answer-box ul {
  display: grid;
  gap: 10px;
  padding: 0;
  list-style: none;
}

.choices li {
  display: block;
}

.choice-button {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  width: 100%;
  min-height: 62px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfcfa;
  color: var(--ink);
  font: inherit;
  text-align: left;
  cursor: pointer;
}

.choice-button:hover:not(:disabled),
.choice-button:focus-visible {
  border-color: rgba(15, 111, 92, 0.55);
  box-shadow: 0 0 0 3px rgba(15, 111, 92, 0.12);
  outline: none;
}

.choice-letter {
  display: grid;
  width: 34px;
  height: 34px;
  place-items: center;
  border-radius: 50%;
  background: var(--surface-soft);
  color: var(--primary-dark);
  font-weight: 900;
}

.choice-text {
  min-width: 0;
}

.choice-button:disabled {
  cursor: default;
}

.choice-button.is-correct {
  border-color: rgba(15, 111, 92, 0.75);
  background: #ecf8f1;
}

.choice-button.is-correct .choice-letter {
  background: var(--primary);
  color: white;
}

.choice-button.is-incorrect {
  border-color: rgba(190, 52, 42, 0.65);
  background: #fff0ee;
}

.choice-button.is-incorrect .choice-letter {
  background: #be342a;
  color: white;
}

.choice-button.is-selected {
  box-shadow: inset 0 0 0 2px rgba(24, 33, 29, 0.08);
}

.retry-button {
  width: 100%;
  margin: 12px 0 20px;
}

.result-panel {
  margin: 18px 0 14px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-soft);
}

.result-panel[hidden] {
  display: none;
}

.result-message {
  margin: 0 0 12px;
  font-size: 1.35rem;
  font-weight: 900;
  line-height: 1.3;
}

.result-message.is-correct {
  color: var(--primary-dark);
}

.result-message.is-incorrect {
  color: #be342a;
}

.result-summary {
  display: grid;
  gap: 8px;
  margin: 0;
}

.result-summary div {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.result-summary dt {
  color: var(--muted);
  font-weight: 800;
}

.result-summary dd {
  margin: 0;
  font-weight: 900;
}

.answer-panel {
  display: grid;
  gap: 14px;
}

.answer-panel[hidden] {
  display: none;
}

.answer-box {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fbfcfa;
}

.answer-box.correct {
  border-color: rgba(15, 111, 92, 0.35);
  background: #ecf8f1;
}

.answer-box.trap {
  border-color: rgba(212, 93, 44, 0.35);
  background: #fff4ec;
}

.pager {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 24px;
}

.pager a {
  min-height: 62px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface-soft);
  text-decoration: none;
  font-weight: 800;
}

.site-footer {
  padding: 24px clamp(16px, 4vw, 44px) 38px;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.84rem;
}

.site-footer p {
  width: min(1120px, 100%);
  margin: 0 auto;
}

@media (max-width: 760px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .nav {
    width: 100%;
    justify-content: flex-start;
  }

  .app {
    width: min(100% - 24px, 1120px);
    padding-top: 20px;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .hero h1,
  .page-title h1 {
    font-size: 2.1rem;
  }

  .hero-title {
    font-size: 1.85rem;
  }

  .split {
    align-items: stretch;
    flex-direction: column;
  }

  .question-row {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .pager {
    grid-template-columns: 1fr;
  }
}

/* fe-portal の iframe 埋め込み時は内部ヘッダーを隠す（二重ヘッダー防止） */
body.embedded .site-header {
  display: none;
}
body.embedded .app {
  padding-top: 1rem;
}