/* CE 414 lecture quizzes — shared stylesheet.
   One engine behind every quiz under docs/quizzes/. Each quiz page supplies only its
   questions; the look, the phone layout and the keyboard handling live here and in quiz.js.
   Derived from the Week 3 "Categorical or Continuous?" pilot, generalized to 2-4 options. */

:root {
  --bg: #f8fafc;
  --card: #ffffff;
  --text: #1e293b;
  --heading: #0f172a;
  --muted: #64748b;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --success: #16a34a;
  --success-bg: #f0fdf4;
  --success-text: #14532d;
  --danger: #dc2626;
  --danger-bg: #fef2f2;
  --danger-text: #7f1d1d;
  --border: #e2e8f0;
  --hover-bg: #eff6ff;
}

/* Phones are the point of these quizzes, and a lecture hall is dark. */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f172a;
    --card: #1e293b;
    --text: #e2e8f0;
    --heading: #f1f5f9;
    --muted: #94a3b8;
    --primary: #60a5fa;
    --primary-hover: #93c5fd;
    --success: #22c55e;
    --success-bg: #14321f;
    --success-text: #bbf7d0;
    --danger: #f87171;
    --danger-bg: #3a1a1a;
    --danger-text: #fecaca;
    --border: #334155;
    --hover-bg: #1e3a5f;
  }
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

body {
  background-color: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
  padding: 2rem 1rem;
}

.container {
  max-width: 680px;
  width: 100%;
}

header {
  text-align: center;
  margin-bottom: 1.5rem;
}

h1 {
  font-size: 1.6rem;
  margin-bottom: 0.5rem;
  color: var(--heading);
}

p.subtitle {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.45;
}

.score-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--card);
  padding: 0.75rem 1.25rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
  font-weight: 500;
}

.progress-track {
  height: 4px;
  background: var(--border);
  border-radius: 2px;
  margin-bottom: 1.25rem;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  width: 0;
  background: var(--primary);
  border-radius: 2px;
  transition: width 0.25s ease-in-out;
}

.quiz-card {
  background: var(--card);
  border-radius: 12px;
  border: 1px solid var(--border);
  padding: 1.75rem;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.question-badge {
  display: inline-block;
  font-size: 0.75rem;
  text-transform: uppercase;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--primary);
  margin-bottom: 0.5rem;
}

.question-prompt {
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  color: var(--heading);
  line-height: 1.3;
}

.question-detail {
  color: var(--muted);
  font-size: 0.95rem;
  margin-bottom: 1.5rem;
  line-height: 1.45;
}

.options {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

/* Three or four choices read better stacked than crammed side by side. */
.options.stacked {
  grid-template-columns: 1fr;
  gap: 0.75rem;
}

button.opt-btn {
  padding: 0.85rem 1rem;
  font-size: 1rem;
  font-weight: 600;
  border: 2px solid var(--border);
  background: var(--card);
  color: var(--text);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.15s ease-in-out;
  text-align: left;
  line-height: 1.35;
}

.options:not(.stacked) button.opt-btn {
  text-align: center;
}

button.opt-btn:hover:not(:disabled) {
  border-color: var(--primary);
  color: var(--primary);
  background: var(--hover-bg);
}

button.opt-btn:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

button.opt-btn:disabled {
  cursor: default;
}

button.opt-btn .key-hint {
  display: inline-block;
  min-width: 1.25em;
  margin-right: 0.5em;
  font-weight: 700;
  color: var(--muted);
}

button.correct {
  background: var(--success) !important;
  border-color: var(--success) !important;
  color: #ffffff !important;
}

button.correct .key-hint,
button.incorrect .key-hint {
  color: rgba(255, 255, 255, 0.75);
}

button.incorrect {
  background: var(--danger) !important;
  border-color: var(--danger) !important;
  color: #ffffff !important;
}

.feedback {
  display: none;
  padding: 1rem;
  border-radius: 8px;
  font-size: 0.95rem;
  line-height: 1.45;
  margin-bottom: 1.25rem;
}

.feedback.visible {
  display: block;
}

.feedback.correct-box {
  background-color: var(--success-bg);
  border-left: 4px solid var(--success);
  color: var(--success-text);
}

.feedback.incorrect-box {
  background-color: var(--danger-bg);
  border-left: 4px solid var(--danger);
  color: var(--danger-text);
}

.feedback strong {
  display: block;
  margin-bottom: 0.25rem;
}

.controls {
  display: flex;
  justify-content: flex-end;
}

button.next-btn {
  padding: 0.65rem 1.4rem;
  font-size: 0.95rem;
  font-weight: 600;
  background: var(--primary);
  color: #ffffff;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  display: none;
}

button.next-btn:hover {
  background: var(--primary-hover);
}

@media (prefers-color-scheme: dark) {
  button.next-btn,
  button.restart-btn { color: #0f172a; }
}

.final-screen {
  display: none;
  text-align: center;
  padding: 2rem 1rem;
}

.final-screen h2 {
  font-size: 1.5rem;
  margin-bottom: 0.75rem;
  color: var(--heading);
}

.final-score {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 1rem;
}

.final-note {
  color: var(--muted);
  margin-bottom: 1.5rem;
  line-height: 1.45;
}

.review {
  text-align: left;
  margin: 1.5rem 0 0;
  border-top: 1px solid var(--border);
  padding-top: 1.25rem;
}

.review h3 {
  font-size: 1rem;
  color: var(--heading);
  margin-bottom: 0.75rem;
}

.review ol {
  padding-left: 1.2rem;
}

.review li {
  margin-bottom: 0.9rem;
  font-size: 0.9rem;
  line-height: 1.45;
  color: var(--muted);
}

.review li strong {
  color: var(--text);
  display: block;
}

.review .ans {
  color: var(--success);
  font-weight: 600;
}

button.restart-btn {
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  background: var(--primary);
  color: #ffffff;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  margin-top: 1rem;
}

footer.page-foot {
  text-align: center;
  margin-top: 1.5rem;
  font-size: 0.8rem;
  color: var(--muted);
  line-height: 1.6;
}

footer.page-foot a {
  color: var(--muted);
}

.kbd-hint {
  display: block;
  margin-top: 0.4rem;
  font-size: 0.75rem;
  color: var(--muted);
}

/* Phones: the quiz is meant to be scanned from a slide and answered on a handset. */
@media (max-width: 480px) {
  body { padding: 1rem 0.75rem; }
  h1 { font-size: 1.3rem; }
  .quiz-card { padding: 1.1rem; }
  .question-prompt { font-size: 1.15rem; }
  .options { gap: 0.6rem; }
  button.opt-btn { padding: 0.9rem 0.6rem; font-size: 0.95rem; }
  .controls { justify-content: stretch; }
  button.next-btn { width: 100%; padding: 0.8rem 1rem; }
  .kbd-hint { display: none; }
}

@media (hover: none) {
  .kbd-hint { display: none; }
  button.opt-btn .key-hint { display: none; }
}