:root {
  color-scheme: light;
  --bg: #f5efe1;
  --surface: rgba(255, 251, 244, 0.92);
  --surface-strong: #fffdfa;
  --ink: #16231f;
  --muted: #5f6e68;
  --line: rgba(26, 47, 42, 0.12);
  --teal: #0b7a75;
  --teal-deep: #0b4f54;
  --gold: #d48c28;
  --coral: #cf6444;
  --sky: #dbeff0;
  --mint: #d9efe7;
  --shadow: 0 24px 60px rgba(27, 41, 36, 0.14);
  --space-1: 6px;
  --space-2: 10px;
  --space-3: 14px;
  --space-4: 18px;
  --space-5: 24px;
  --space-6: 32px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family:
    "Source Sans 3",
    "Proxima Nova",
    "Avenir Next",
    "Segoe UI",
    sans-serif;
  color: var(--ink);
  background:
    radial-gradient(circle at top left, rgba(212, 140, 40, 0.12), transparent 30%),
    radial-gradient(circle at right 20%, rgba(11, 122, 117, 0.12), transparent 28%),
    linear-gradient(180deg, #fbf7ee 0%, var(--bg) 38%, #efe6d2 100%);
}

button,
a {
  font: inherit;
}

a {
  color: var(--teal-deep);
}

button {
  border: 0;
}

.page-glow {
  position: fixed;
  width: 18rem;
  aspect-ratio: 1;
  border-radius: 999px;
  filter: blur(70px);
  opacity: 0.5;
  pointer-events: none;
}

.glow-a {
  top: 5rem;
  right: 8vw;
  background: rgba(11, 122, 117, 0.16);
}

.glow-b {
  bottom: 4rem;
  left: 2rem;
  background: rgba(212, 140, 40, 0.16);
}

.app-shell {
  width: min(1180px, calc(100% - 28px));
  margin: 0 auto;
  padding: var(--space-4) 0 var(--space-6);
  display: grid;
  gap: var(--space-4);
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 0;
  box-shadow: var(--shadow);
  backdrop-filter: blur(8px);
  padding: var(--space-5);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, 0.8fr);
  gap: var(--space-4);
  align-items: stretch;
}

.hero-copy,
.section-head,
.game-stack,
.match-shell {
  display: grid;
  gap: var(--space-3);
}

.eyebrow,
.section-kicker,
.panel-label {
  margin: 0;
  color: var(--teal);
  text-transform: uppercase;
  font-weight: 800;
  letter-spacing: 0.08em;
  font-size: 0.78rem;
}

h1,
h2,
h3,
.countdown strong {
  font-family:
    "Source Sans 3",
    "Proxima Nova",
    "Avenir Next",
    "Segoe UI",
    sans-serif;
  margin: 0;
  line-height: 1;
  letter-spacing: -0.02em;
}

h1 {
  font-size: clamp(3rem, 8vw, 5.6rem);
}

h2 {
  font-size: clamp(1.7rem, 4vw, 2.7rem);
}

h3 {
  font-size: clamp(1.35rem, 2.8vw, 1.8rem);
}

.lede,
.section-note,
.fine-print,
.muted,
.source-list li,
.study-step span,
.badge-card p,
.game-summary p,
.game-question-head p,
.unit-card li,
.frq-card li {
  color: var(--muted);
  line-height: 1.58;
}

.lede,
.section-note,
.fine-print,
.muted {
  margin: 0;
}

.hero-actions,
.quiz-actions,
.pill-row,
.quiz-toolbar,
.quiz-topline,
.game-topline,
.game-scoreline {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  align-items: center;
}

.primary-btn,
.ghost-btn,
.mode-pill,
.answer-btn {
  min-height: 46px;
  border-radius: 0;
  padding: 11px 16px;
  transition:
    transform 0.18s ease,
    border-color 0.18s ease,
    background 0.18s ease;
}

.primary-btn,
.ghost-btn {
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  cursor: pointer;
}

.primary-btn {
  color: #fffaf3;
  background: linear-gradient(135deg, var(--teal), var(--teal-deep));
}

.ghost-btn,
.mode-pill,
.answer-btn {
  background: rgba(255, 255, 255, 0.76);
  border: 1px solid var(--line);
  color: var(--ink);
}

.primary-btn:hover,
.ghost-btn:hover,
.mode-pill:hover,
.answer-btn:hover,
.primary-btn:focus-visible,
.ghost-btn:focus-visible,
.mode-pill:focus-visible,
.answer-btn:focus-visible {
  transform: translateY(-1px);
}

.exam-panel,
.quiz-card-shell,
.game-card,
.mini-card,
.section-card,
.unit-card,
.frq-card,
.study-step,
.badge-card {
  background: var(--surface-strong);
  border: 1px solid var(--line);
  border-radius: 0;
}

.exam-panel,
.quiz-card-shell,
.game-card,
.mini-card,
.section-card,
.unit-card,
.frq-card,
.study-step,
.badge-card {
  padding: var(--space-3);
}

.exam-panel {
  display: grid;
  gap: var(--space-4);
}

.countdown {
  display: grid;
  gap: 4px;
}

.countdown strong {
  font-size: clamp(1.9rem, 5vw, 3rem);
}

.exam-facts {
  display: grid;
  gap: var(--space-2);
  margin: 0;
}

.exam-facts div {
  display: grid;
  grid-template-columns: 84px 1fr;
  gap: 10px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
}

.exam-facts div:first-child {
  border-top: 0;
  padding-top: 0;
}

.exam-facts dt,
.quiz-stats,
.game-scoreline span {
  color: var(--muted);
  font-weight: 700;
}

.exam-facts dd {
  margin: 0;
  font-weight: 800;
}

.overview-grid,
.review-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: var(--space-4);
}

.mini-grid,
.section-grid,
.unit-grid,
.flashcard-grid,
.frq-grid,
.badge-grid,
.match-unit-grid,
.match-topic-grid {
  display: grid;
  gap: var(--space-3);
}

.mini-grid {
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.section-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.chip,
.pill {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 5px 10px;
  border-radius: 0;
  font-size: 0.84rem;
  font-weight: 800;
}

.chip {
  background: var(--mint);
  color: var(--teal-deep);
}

.pill {
  background: var(--sky);
  color: var(--teal-deep);
}

.quiz-zone {
  background:
    linear-gradient(180deg, rgba(219, 239, 240, 0.7), rgba(255, 251, 244, 0.96)),
    var(--surface);
}

.quiz-toolbar {
  justify-content: space-between;
  margin-bottom: var(--space-4);
}

.mode-pill {
  cursor: pointer;
  font-weight: 800;
}

.mode-pill.active {
  background: var(--teal-deep);
  color: #fff;
  border-color: var(--teal-deep);
}

.quiz-card-shell {
  display: grid;
  gap: var(--space-3);
}

.answer-grid {
  display: grid;
  gap: var(--space-2);
}

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

.answer-btn {
  width: 100%;
  text-align: left;
  cursor: pointer;
  padding-inline: 18px;
  border-radius: 0;
  min-height: 58px;
  font-weight: 700;
}

.answer-btn.correct {
  background: var(--mint);
  border-color: rgba(11, 122, 117, 0.25);
}

.answer-btn.incorrect {
  background: rgba(207, 100, 68, 0.13);
  border-color: rgba(207, 100, 68, 0.28);
}

.feedback {
  border-radius: 0;
  padding: var(--space-3);
  background: rgba(255, 247, 232, 0.9);
  border: 1px solid rgba(212, 140, 40, 0.2);
}

.feedback strong {
  display: block;
  margin-bottom: var(--space-1);
}

.feedback span {
  display: block;
  line-height: 1.58;
}

.feedback.hidden {
  display: none;
}

.game-stack,
.badge-grid {
  gap: var(--space-3);
}

.game-card {
  display: grid;
  gap: var(--space-3);
}

.game-topline > div {
  display: grid;
  gap: var(--space-1);
}

.game-topline {
  justify-content: space-between;
}

.game-scoreline {
  justify-content: space-between;
  padding-block: var(--space-1);
}

.game-scoreline strong {
  font-size: 1.5rem;
}

.game-question {
  min-height: 120px;
}

.game-question-head {
  display: grid;
  gap: var(--space-1);
  margin-bottom: var(--space-3);
}

.game-summary {
  display: grid;
  gap: var(--space-1);
}

.badge-grid {
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.badge-card.unlocked {
  background: linear-gradient(180deg, rgba(217, 239, 231, 0.9), rgba(255, 253, 250, 1));
  border-color: rgba(11, 122, 117, 0.25);
}

.unit-grid {
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
}

.unit-card header {
  display: grid;
  gap: var(--space-1);
}

.unit-card p {
  margin: 0;
}

.unit-card ul,
.section-card ul,
.frq-card ul,
.source-list {
  margin: var(--space-2) 0 0;
  padding-left: 18px;
}

.flashcard-grid {
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
}

.flashcard {
  min-height: 180px;
  padding: 16px;
  cursor: pointer;
  perspective: 1000px;
  border: 1px solid var(--line);
  border-radius: 0;
  background: var(--surface-strong);
}

.flashcard-inner {
  position: relative;
  width: 100%;
  min-height: 148px;
  transform-style: preserve-3d;
  transition: transform 0.5s ease;
}

.flashcard.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

.flashcard-face {
  position: absolute;
  inset: 0;
  border-radius: 0;
  backface-visibility: hidden;
  display: grid;
  align-content: space-between;
  gap: 10px;
}

.flashcard-back {
  transform: rotateY(180deg);
}

.frq-grid {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.match-unit-grid {
  grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
}

.match-topic-grid {
  grid-template-columns: 1fr;
}

.study-mix {
  display: grid;
  gap: var(--space-3);
}

.study-step {
  display: grid;
  gap: var(--space-1);
}

.source-list {
  display: grid;
  gap: var(--space-3);
}

.source-list a {
  font-weight: 800;
}

@media (max-width: 860px) {
  .hero,
  .overview-grid,
  .review-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .app-shell {
    width: min(100%, calc(100% - 18px));
    padding-top: var(--space-2);
  }

  .card,
  .exam-panel,
  .quiz-card-shell,
  .game-card,
  .mini-card,
  .section-card,
  .unit-card,
  .frq-card,
  .study-step,
  .badge-card,
  .flashcard {
    border-radius: 0;
  }

  .exam-facts div {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .quiz-toolbar,
  .game-topline,
  .game-scoreline {
    align-items: flex-start;
  }
}