:root {
  color-scheme: light;
  --ink: #15383e;
  --ink-strong: #0d2a2f;
  --muted: #526b6f;
  --subtle: #6e8184;
  --canvas: #f2f6f5;
  --surface: #ffffff;
  --surface-soft: #e9f1ef;
  --line: #ccdcda;
  --line-strong: #9ebbb7;
  --teal: #176e70;
  --teal-dark: #105457;
  --teal-light: #d9ece8;
  --correct: #1d7355;
  --correct-soft: #e1f2e9;
  --wrong: #a3453f;
  --wrong-soft: #fae9e7;
  --warning: #8a6521;
  --warning-soft: #f6eedb;
  --shadow: 0 24px 70px rgba(19, 57, 62, 0.11);
  --radius-lg: 28px;
  --radius-md: 18px;
  --radius-sm: 12px;
  --max-width: 1240px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 8% 4%, rgba(107, 174, 163, 0.17), transparent 27rem),
    linear-gradient(180deg, #f6f9f8 0, var(--canvas) 36rem);
  color: var(--ink);
  font-family: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

button {
  font: inherit;
}

a {
  color: var(--teal-dark);
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--ink-strong);
}

:focus-visible {
  outline: 3px solid #d38b24;
  outline-offset: 4px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  z-index: 100;
  top: 0.75rem;
  left: 0.75rem;
  padding: 0.7rem 1rem;
  border-radius: 8px;
  background: var(--ink-strong);
  color: white;
  font-weight: 700;
  transform: translateY(-160%);
  transition: transform 150ms ease;
}

.skip-link:focus {
  color: white;
  transform: translateY(0);
}

.page-shell {
  width: min(calc(100% - 40px), var(--max-width));
  margin: 0 auto;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  min-height: 116px;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.8rem;
  color: var(--ink-strong);
  text-decoration: none;
}

.brand-mark {
  display: grid;
  width: 46px;
  height: 46px;
  place-items: center;
  border: 1px solid var(--ink);
  border-radius: 50%;
  background: var(--surface);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.5rem;
  font-weight: 700;
  line-height: 1;
  box-shadow: inset 0 0 0 5px var(--surface-soft);
}

.brand-name,
.brand-subtitle {
  display: block;
}

.brand-name {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.1;
}

.brand-subtitle {
  margin-top: 0.16rem;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.header-meta {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.55rem;
}

.scope-chip,
.safety-chip {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0.3rem 0.75rem;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.035em;
}

.scope-chip {
  border: 1px solid var(--line-strong);
  background: rgba(255, 255, 255, 0.7);
  color: var(--ink);
}

.safety-chip {
  background: var(--warning-soft);
  color: #6f4c10;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(280px, 0.75fr);
  gap: clamp(3rem, 8vw, 7.5rem);
  align-items: end;
  padding: clamp(4rem, 8vw, 7.5rem) 0 clamp(3.5rem, 7vw, 6rem);
}

.eyebrow {
  margin: 0 0 0.9rem;
  color: var(--teal-dark);
  font-size: 0.76rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 830px;
  margin: 0;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2.8rem, 6.5vw, 5.7rem);
  font-weight: 400;
  letter-spacing: -0.045em;
  line-height: 0.98;
}

.hero h1 em {
  color: var(--teal);
  font-weight: 400;
}

.hero-lede {
  max-width: 670px;
  margin: 1.65rem 0 0;
  color: var(--muted);
  font-size: clamp(1.05rem, 2vw, 1.2rem);
  line-height: 1.7;
}

.hero-definitions {
  margin: 0;
  border-top: 1px solid var(--line-strong);
}

.hero-definitions > div {
  display: grid;
  grid-template-columns: 5.5rem 1fr;
  gap: 1.25rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--line);
}

.hero-definitions dt {
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1rem;
  font-weight: 700;
}

.hero-definitions dd {
  margin: 0;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.5;
}

.study-layout {
  display: grid;
  grid-template-columns: minmax(245px, 0.65fr) minmax(0, 1.6fr);
  gap: clamp(1.25rem, 3.5vw, 3rem);
  align-items: start;
  padding-bottom: 2.5rem;
}

.study-panel {
  display: flex;
  flex-direction: column;
  gap: 1.75rem;
  padding: 1.4rem 0;
}

.study-panel h2 {
  margin: 0;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1.55rem, 3vw, 2.15rem);
  font-weight: 400;
  letter-spacing: -0.025em;
  line-height: 1.16;
}

.study-panel > div > p:last-child {
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 0.94rem;
}

.study-note {
  display: grid;
  grid-template-columns: 2.3rem 1fr;
  gap: 0.8rem;
  padding-top: 1.15rem;
  border-top: 1px solid var(--line);
}

.study-note-index {
  color: var(--teal);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 0.88rem;
  font-variant-numeric: tabular-nums;
}

.study-note h3 {
  margin: 0;
  color: var(--ink-strong);
  font-size: 0.9rem;
  letter-spacing: 0.01em;
}

.study-note p {
  margin: 0.35rem 0 0;
  color: var(--muted);
  font-size: 0.84rem;
  line-height: 1.5;
}

.resource-links {
  display: flex;
  flex-direction: column;
  border-top: 1px solid var(--line-strong);
}

.resource-links a {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink);
  font-size: 0.82rem;
  font-weight: 700;
  text-decoration: none;
}

.resource-links a:hover {
  color: var(--teal-dark);
}

.quiz-card {
  min-height: 680px;
  padding: clamp(1.3rem, 4vw, 3.2rem);
  border: 1px solid rgba(153, 185, 181, 0.7);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.94);
  box-shadow: var(--shadow);
}

.quiz-status {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 2rem;
  align-items: center;
  padding-bottom: 1.8rem;
  border-bottom: 1px solid var(--line);
}

.progress-labels {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.55rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

progress {
  display: block;
  width: 100%;
  height: 7px;
  overflow: hidden;
  border: 0;
  border-radius: 999px;
  background: var(--surface-soft);
  color: var(--teal);
}

progress::-webkit-progress-bar {
  border-radius: 999px;
  background: var(--surface-soft);
}

progress::-webkit-progress-value {
  border-radius: 999px;
  background: var(--teal);
  transition: width 260ms ease;
}

progress::-moz-progress-bar {
  border-radius: 999px;
  background: var(--teal);
}

.scoreboard {
  display: flex;
  gap: 1.4rem;
  margin: 0;
}

.scoreboard > div {
  min-width: 58px;
}

.scoreboard dt {
  color: var(--subtle);
  font-size: 0.68rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.scoreboard dd {
  margin: 0.1rem 0 0;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.55rem;
  font-variant-numeric: tabular-nums;
  font-weight: 700;
  line-height: 1;
}

.score-total {
  color: var(--subtle);
  font-size: 0.75rem;
}

.question-block {
  padding: clamp(2rem, 5vw, 3.5rem) 0 1.6rem;
}

.question-kicker {
  margin: 0 0 0.6rem;
  color: var(--teal-dark);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.question-block h2 {
  max-width: 760px;
  margin: 0;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 400;
  letter-spacing: -0.025em;
  line-height: 1.15;
}

.question-block h2:focus {
  outline: none;
}

.question-hint {
  margin: 0.8rem 0 0;
  color: var(--muted);
  font-size: 0.86rem;
}

kbd {
  display: inline-grid;
  min-width: 1.55em;
  min-height: 1.55em;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-bottom-width: 2px;
  border-radius: 5px;
  background: var(--surface);
  color: var(--ink);
  font-family: inherit;
  font-size: 0.75em;
  font-weight: 800;
  line-height: 1;
}

.answer-list {
  display: grid;
  gap: 0.75rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.answer-choice {
  display: grid;
  grid-template-columns: 2.25rem 1fr auto;
  gap: 1rem;
  align-items: center;
  width: 100%;
  min-height: 76px;
  padding: 0.8rem 1.15rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--ink-strong);
  cursor: pointer;
  text-align: left;
  transition: border-color 150ms ease, background-color 150ms ease, transform 150ms ease;
}

.answer-choice:not(:disabled):hover {
  border-color: var(--teal);
  background: #f8fbfa;
  transform: translateY(-1px);
}

.answer-choice:disabled {
  cursor: default;
  opacity: 1;
}

.choice-key {
  display: grid;
  width: 2.1rem;
  height: 2.1rem;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 800;
}

.choice-value {
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.3rem;
  font-variant-numeric: tabular-nums;
  font-weight: 700;
}

.choice-unit {
  color: var(--subtle);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.answer-choice.is-correct {
  border-color: var(--correct);
  background: var(--correct-soft);
  box-shadow: inset 4px 0 0 var(--correct);
}

.answer-choice.is-correct .choice-key {
  border-color: var(--correct);
  background: var(--correct);
  color: white;
}

.answer-choice.is-wrong {
  border-color: var(--wrong);
  background: var(--wrong-soft);
  box-shadow: inset 4px 0 0 var(--wrong);
}

.answer-choice.is-wrong .choice-key {
  border-color: var(--wrong);
  background: var(--wrong);
  color: white;
}

.feedback-panel {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 1.25rem;
  align-items: end;
  margin-top: 1rem;
  padding: 1.2rem;
  border-radius: var(--radius-sm);
  background: var(--surface-soft);
}

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

.feedback-panel.is-correct {
  background: var(--correct-soft);
}

.feedback-panel.is-wrong {
  background: var(--wrong-soft);
}

.feedback-status {
  margin: 0 0 0.25rem;
  color: var(--teal-dark);
  font-size: 0.7rem;
  font-weight: 900;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.feedback-panel.is-correct .feedback-status {
  color: var(--correct);
}

.feedback-panel.is-wrong .feedback-status {
  color: var(--wrong);
}

.feedback-panel h3 {
  margin: 0;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.2rem;
}

.feedback-panel p:last-child {
  margin: 0.3rem 0 0;
  color: var(--muted);
  font-size: 0.86rem;
}

.primary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  min-height: 48px;
  padding: 0.72rem 1rem;
  border: 1px solid var(--teal-dark);
  border-radius: 10px;
  background: var(--teal-dark);
  color: white;
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 800;
  text-decoration: none;
  transition: background-color 150ms ease, transform 150ms ease;
}

.primary-button:hover {
  background: var(--ink-strong);
  color: white;
  transform: translateY(-1px);
}

.completion-view {
  min-height: 590px;
  padding: clamp(1.5rem, 5vw, 3.2rem) 0 0;
}

.completion-view[hidden] {
  display: none;
}

.completion-view h2 {
  max-width: 660px;
  margin: 0;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: clamp(2rem, 5vw, 3.6rem);
  font-weight: 400;
  letter-spacing: -0.035em;
  line-height: 1.05;
}

.completion-view h2:focus {
  outline: none;
}

.completion-message {
  max-width: 660px;
  margin: 1rem 0 0;
  color: var(--muted);
}

.completion-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.7rem;
  margin: 2rem 0;
}

.completion-stats > div {
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: #f9fbfa;
}

.completion-stats dt {
  color: var(--subtle);
  font-size: 0.7rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.completion-stats dd {
  margin: 0.25rem 0 0;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.7rem;
  font-variant-numeric: tabular-nums;
  font-weight: 700;
}

.missed-review {
  margin-bottom: 1.5rem;
  padding-top: 1.3rem;
  border-top: 1px solid var(--line);
}

.missed-review h3 {
  margin: 0 0 0.75rem;
  color: var(--ink-strong);
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.2rem;
}

.missed-review ul {
  display: grid;
  gap: 0.55rem;
  margin: 0;
  padding-left: 1.25rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.all-correct {
  margin: 0;
  color: var(--correct);
  font-weight: 800;
}

.restart-button {
  width: 100%;
}

.noscript-message {
  padding: 1rem;
  border: 1px solid var(--wrong);
  border-radius: 10px;
  background: var(--wrong-soft);
  color: var(--wrong);
  font-weight: 700;
}

.disclaimer {
  display: grid;
  grid-template-columns: 2.6rem 1fr;
  gap: 1rem;
  align-items: start;
  margin: 1.5rem 0 2.5rem;
  padding: clamp(1.1rem, 3vw, 1.5rem);
  border: 1px solid #d8c59a;
  border-radius: var(--radius-md);
  background: var(--warning-soft);
  color: #5f481b;
}

.disclaimer-mark {
  display: grid;
  width: 2.4rem;
  height: 2.4rem;
  place-items: center;
  border: 1px solid currentColor;
  border-radius: 50%;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 1.1rem;
  font-weight: 700;
}

.disclaimer h2 {
  margin: 0;
  color: #5a4012;
  font-size: 0.9rem;
}

.disclaimer p {
  margin: 0.3rem 0 0;
  font-size: 0.83rem;
  line-height: 1.55;
}

.site-footer {
  display: flex;
  justify-content: space-between;
  gap: 2rem;
  padding: 1.75rem 0 2.5rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.77rem;
}

.site-footer p {
  margin: 0;
}

.site-footer a {
  font-weight: 800;
  text-decoration: none;
}

@media (max-width: 900px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 2.5rem;
  }

  .hero-definitions {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
  }

  .hero-definitions > div {
    display: block;
    padding: 1rem;
    border: 1px solid var(--line);
    border-right: 0;
  }

  .hero-definitions > div:last-child {
    border-right: 1px solid var(--line);
  }

  .hero-definitions dd {
    margin-top: 0.35rem;
  }

  .study-layout {
    grid-template-columns: 1fr;
  }

  .study-panel {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.2rem 2rem;
  }

  .study-panel > div:first-child,
  .resource-links {
    grid-column: 1 / -1;
  }
}

@media (max-width: 640px) {
  .page-shell {
    width: min(calc(100% - 24px), var(--max-width));
  }

  .site-header {
    align-items: flex-start;
    flex-direction: column;
    gap: 1rem;
    padding: 1.25rem 0;
  }

  .header-meta {
    justify-content: flex-start;
  }

  .hero {
    padding: 3rem 0;
  }

  .hero h1 {
    font-size: clamp(2.55rem, 15vw, 4rem);
  }

  .hero-definitions {
    grid-template-columns: 1fr;
  }

  .hero-definitions > div,
  .hero-definitions > div:last-child {
    display: grid;
    grid-template-columns: 5.3rem 1fr;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    border-left: 0;
  }

  .study-panel {
    grid-template-columns: 1fr;
  }

  .study-panel > div:first-child,
  .resource-links {
    grid-column: auto;
  }

  .quiz-card {
    min-height: 0;
    padding: 1.2rem;
    border-radius: 20px;
  }

  .quiz-status {
    grid-template-columns: 1fr;
    gap: 1.15rem;
  }

  .scoreboard {
    justify-content: space-between;
  }

  .scoreboard > div {
    flex: 1;
    padding-right: 1rem;
    border-right: 1px solid var(--line);
  }

  .scoreboard > div:last-child {
    border-right: 0;
  }

  .question-block {
    padding-top: 2rem;
  }

  .answer-choice {
    min-height: 68px;
  }

  .feedback-panel {
    grid-template-columns: 1fr;
    align-items: start;
  }

  .primary-button {
    width: 100%;
  }

  .completion-stats {
    grid-template-columns: 1fr;
  }

  .completion-stats > div {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

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

  .site-footer {
    flex-direction: column;
    gap: 0.6rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media print {
  .skip-link,
  .header-meta,
  .answer-list,
  .feedback-panel,
  .primary-button,
  .site-footer {
    display: none !important;
  }

  body {
    background: white;
  }

  .page-shell {
    width: 100%;
  }

  .quiz-card {
    min-height: 0;
    box-shadow: none;
  }
}