:root {
  --navy-950: #071c2c;
  --navy-900: #0b2a40;
  --navy-700: #164d6b;
  --blue-600: #087fa6;
  --blue-500: #08a6c9;
  --blue-100: #dff6fa;
  --sand-50: #fbfaf6;
  --orange-500: #f59e0b;
  --green-700: #13734c;
  --green-100: #e4f7ed;
  --red-700: #b42334;
  --red-100: #fdebed;
  --ink: #17232c;
  --muted: #687781;
  --line: #dce4e8;
  --white: #fff;
  --shadow: 0 14px 36px rgba(7, 28, 44, .08);
}

* { box-sizing: border-box; }

html {
  min-height: 100%;
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  background: radial-gradient(circle at 95% 0%, rgba(8, 166, 201, .11), transparent 26rem), var(--sand-50);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
}

a { color: inherit; }

.page-shell {
  width: min(1120px, calc(100% - 40px));
  margin-inline: auto;
}

.site-nav {
  color: var(--white);
  background: var(--navy-950);
  border-bottom: 3px solid var(--blue-500);
}

.nav-inner {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand, .home-link {
  color: var(--white);
  text-decoration: none;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 1.15rem;
  letter-spacing: -.02em;
}

.brand-mark {
  display: grid;
  width: 40px;
  height: 40px;
  place-items: center;
  color: var(--navy-950);
  background: var(--white);
  border-radius: 12px;
  font-size: 1.35rem;
}

.home-link {
  padding: 8px 12px;
  color: #c8d8e1;
  border-radius: 8px;
  font-size: .92rem;
  font-weight: 650;
}

.home-link:hover, .home-link:focus-visible {
  color: var(--white);
  background: rgba(255, 255, 255, .1);
}

.site-main {
  min-height: calc(100vh - 164px);
  padding: 40px 0 72px;
}

.site-footer {
  padding: 22px 0;
  color: #83939d;
  background: var(--navy-950);
  font-size: .85rem;
}

.hero {
  max-width: 760px;
  padding: 44px 0 36px;
}

.eyebrow {
  display: inline-block;
  margin-bottom: 9px;
  color: var(--blue-600);
  font-size: .76rem;
  font-weight: 800;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.hero h1, .page-heading h1, .quiz-header h1 {
  margin: 0;
  color: var(--navy-950);
  font-weight: 780;
  letter-spacing: -.04em;
}

.hero h1 {
  font-size: clamp(2.2rem, 6vw, 4.3rem);
  line-height: 1.02;
}

.hero p, .page-heading p {
  margin: 16px 0 0;
  color: var(--muted);
  font-size: 1.05rem;
}

.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 30px;
  color: var(--muted);
  font-size: .86rem;
}

.breadcrumbs a {
  color: var(--blue-600);
  font-weight: 650;
  text-decoration: none;
}

.breadcrumbs a:hover { text-decoration: underline; }

.page-heading { margin-bottom: 30px; }
.page-heading h1 { font-size: clamp(1.9rem, 5vw, 3rem); }

.card-grid { display: grid; gap: 18px; }
.category-grid, .year-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.selection-card {
  position: relative;
  display: flex;
  align-items: center;
  gap: 18px;
  min-width: 0;
  padding: 22px;
  color: var(--ink);
  background: rgba(255, 255, 255, .92);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: 0 5px 18px rgba(7, 28, 44, .035);
  text-decoration: none;
  transition: transform .18s ease, border-color .18s ease, box-shadow .18s ease;
}

.selection-card:hover, .selection-card:focus-visible {
  color: var(--ink);
  border-color: var(--blue-500);
  box-shadow: var(--shadow);
  transform: translateY(-2px);
  outline: none;
}

.category-code, .topic-index {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 58px;
  height: 58px;
  color: var(--white);
  background: var(--navy-900);
  border-radius: 15px;
  font-size: 1.35rem;
  font-weight: 800;
}

.topic-index {
  width: 42px;
  height: 42px;
  color: var(--navy-900);
  background: var(--blue-100);
  border-radius: 50%;
  font-size: .92rem;
}

.card-content {
  min-width: 0;
  display: flex;
  flex: 1;
  flex-direction: column;
  gap: 6px;
}

.card-content strong {
  color: var(--navy-950);
  font-size: 1.03rem;
}

.card-content small { color: var(--muted); }

.card-arrow {
  flex: 0 0 auto;
  color: var(--blue-600);
  font-weight: 800;
}

.topic-list { display: grid; gap: 12px; }

.topic-card {
  padding: 18px 20px;
  border-radius: 14px;
}

.badge-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px;
}

.year-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 9px;
  color: var(--navy-700);
  background: #edf3f5;
  border-radius: 999px;
  font-size: .76rem;
  font-weight: 700;
}

.year-badge.current {
  color: #07677f;
  background: var(--blue-100);
}

.year-badge { font-variant-numeric: tabular-nums; }
.year-card { min-height: 126px; }

.year-number {
  color: var(--orange-500);
  font-size: 1.55rem;
  font-weight: 850;
  letter-spacing: -.04em;
}

.start-arrow { font-size: .86rem; }

.alert-card, .empty-state {
  padding: 20px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 14px;
}

.alert-error {
  color: var(--red-700);
  background: var(--red-100);
  border-color: #f2bac2;
}

.empty-state { color: var(--muted); text-align: center; }

.quiz-header {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: end;
  gap: 12px 24px;
  margin-bottom: 22px;
}

.quiz-header h1 { font-size: clamp(1.45rem, 4vw, 2.15rem); }

.progress-label {
  color: var(--muted);
  font-size: .82rem;
  font-weight: 700;
}

.progress-track {
  grid-column: 1 / -1;
  height: 8px;
  overflow: hidden;
  background: #dfe8eb;
  border-radius: 999px;
}

.progress-track span {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--blue-600), var(--blue-500));
  border-radius: inherit;
  transition: width .3s ease;
}

.question-card {
  padding: clamp(22px, 5vw, 42px);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 22px;
  box-shadow: var(--shadow);
}

.question-card h2 {
  max-width: 900px;
  margin: 0 0 26px;
  color: var(--navy-950);
  font-size: clamp(1.2rem, 3vw, 1.65rem);
  line-height: 1.38;
}

.question-media, .answer-media {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.question-media { margin: -6px 0 28px; }

.question-media img {
  width: min(100%, 680px);
  max-height: 460px;
  object-fit: contain;
  background: var(--sand-50);
  border: 1px solid var(--line);
  border-radius: 14px;
}

.answers {
  display: grid;
  gap: 12px;
  min-width: 0;
  margin: 0 0 22px;
  padding: 0;
  border: 0;
}

.answer-option {
  position: relative;
  display: flex;
  align-items: flex-start;
  gap: 14px;
  min-width: 0;
  padding: 16px;
  background: var(--sand-50);
  border: 2px solid transparent;
  border-radius: 14px;
  cursor: pointer;
  transition: border-color .15s ease, background .15s ease;
}

.answer-option:hover, .answer-option:has(input:checked) {
  background: var(--blue-100);
  border-color: var(--blue-500);
}

.answer-option:has(input:focus-visible) {
  outline: 3px solid rgba(8, 166, 201, .3);
  outline-offset: 2px;
}

.answer-option input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
}

.answer-marker {
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  color: var(--navy-700);
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 50%;
  font-size: .86rem;
  font-weight: 800;
}

.answer-content {
  min-width: 0;
  display: flex;
  flex: 1;
  flex-direction: column;
  gap: 12px;
}

.answer-text { padding-top: 5px; font-weight: 570; }

.answer-media img {
  width: min(100%, 320px);
  max-height: 240px;
  object-fit: contain;
  background: var(--white);
  border-radius: 9px;
}

.answer-option.is-correct,
.answer-option.is-correct:hover,
.answer-option.is-correct:has(input:checked) {
  color: var(--green-700);
  background: var(--green-100);
  border-color: #43aa7b;
}

.answer-option.is-incorrect,
.answer-option.is-incorrect:hover,
.answer-option.is-incorrect:has(input:checked) {
  color: var(--red-700);
  background: var(--red-100);
  border-color: #dc6a78;
}

.answer-option.is-muted,
.answer-option.is-muted:hover { color: #89959d; background: #f4f6f6; border-color: transparent; }

.result-icon {
  flex: 0 0 auto;
  font-size: 1.5rem;
  font-weight: 900;
  line-height: 1;
}

.primary-button, .secondary-button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 11px 18px;
  border-radius: 11px;
  font: inherit;
  font-size: .92rem;
  font-weight: 750;
  text-decoration: none;
  cursor: pointer;
}

.primary-button {
  color: var(--white);
  background: var(--navy-900);
  border: 1px solid var(--navy-900);
}

.primary-button:hover, .primary-button:focus-visible {
  color: var(--white);
  background: var(--blue-600);
  border-color: var(--blue-600);
}

.secondary-button {
  color: var(--navy-900);
  background: var(--white);
  border: 1px solid var(--line);
}

.secondary-button:hover, .secondary-button:focus-visible {
  color: var(--navy-900);
  border-color: var(--blue-500);
}

.feedback {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-top: 22px;
  padding: 16px 18px;
  border-radius: 12px;
}

.feedback-correct { color: var(--green-700); background: var(--green-100); }
.feedback-incorrect { color: var(--red-700); background: var(--red-100); }

.explanation {
  margin-top: 16px;
  padding: 16px 18px;
  color: var(--navy-700);
  background: #edf6f8;
  border-left: 4px solid var(--blue-500);
  border-radius: 4px 12px 12px 4px;
}

.explanation p { margin: 5px 0 0; }

.quiz-navigation {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  margin-top: 22px;
}

@media (max-width: 720px) {
  .page-shell { width: min(100% - 24px, 1120px); }
  .nav-inner { min-height: 62px; }
  .brand-mark { width: 34px; height: 34px; border-radius: 10px; font-size: 1.1rem; }
  .site-main { padding-top: 26px; }
  .hero { padding: 28px 0; }
  .category-grid, .year-grid { grid-template-columns: 1fr; }
  .selection-card { padding: 16px; }
  .category-code { width: 48px; height: 48px; border-radius: 12px; font-size: 1.15rem; }
  .topic-card { align-items: flex-start; }
  .topic-index { width: 34px; height: 34px; }
  .start-arrow { font-size: 0; }
  .start-arrow::after { content: "→"; font-size: 1rem; }
  .question-card { border-radius: 16px; }
  .answer-option { padding: 13px; }
  .answer-marker { width: 30px; height: 30px; }
  .quiz-navigation .primary-button, .quiz-navigation .secondary-button { flex: 1; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: .01ms !important;
  }
}