:root {
  --bg: #f5f9f7;
  --card: #ffffff;
  --text: #173528;
  --muted: #5a6f64;
  --accent: #1a7a4c;
  --warn-bg: #fff3cd;
  --warn-bd: #e6d089;
  --border: #c5d9cc;
  --sticky: #0f2a1c;
  font-family: system-ui, -apple-system, Segoe UI, sans-serif;
  line-height: 1.45;
  color: var(--text);
  background: var(--bg);
}
* { box-sizing: border-box; }
body { margin: 0; padding: 0 1rem 5rem; max-width: 44rem; margin-inline: auto; }
a { color: var(--accent); }
.energy-sticky {
  position: sticky; top: 0; z-index: 40;
  background: var(--sticky); color: #fff;
  padding: 0.6rem 1rem;
  display: flex; gap: 0.75rem; align-items: center; flex-wrap: wrap;
  margin: 0 -1rem 1rem;
}
.energy-sticky #energy-total { font-weight: 700; font-variant-numeric: tabular-nums; }
.banner {
  background: var(--warn-bg); border: 1px solid var(--warn-bd);
  border-radius: 10px; padding: 12px 14px; margin: 12px 0; font-size: 0.95rem;
}
.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: 12px; padding: 16px; margin: 16px 0;
}
.card h2 { margin: 0 0 0.5rem; font-size: 1.15rem; }
.muted { color: var(--muted); font-size: 0.9rem; }
.grid { display: grid; gap: 0.65rem; }
@media (min-width: 520px) { .grid.cols-2 { grid-template-columns: 1fr 1fr; } }
.btn {
  display: inline-block; padding: 0.7rem 1rem; border-radius: 10px;
  border: 1px solid var(--border); background: #e8f3ec; color: var(--text);
  text-decoration: none; font: inherit; cursor: pointer; min-height: 44px;
}
.btn.primary { background: #d4edd9; border-color: var(--accent); font-weight: 600; }
.btn:hover { border-color: var(--accent); }
.nav-row { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 0.75rem 0; }
.challenge {
  border: 1px solid var(--border); border-radius: 10px;
  padding: 12px 14px; margin: 10px 0; background: #fafcfb;
}
.challenge h3 { margin: 0 0 0.35rem; font-size: 1rem; }
.challenge .label-bonus {
  display: inline-block; font-size: 0.75rem; font-weight: 700;
  background: #e8f3ec; color: var(--accent); padding: 2px 8px;
  border-radius: 999px; margin-bottom: 6px;
}
.challenge details { margin-top: 8px; }
.challenge .actions { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-top: 10px; }
.challenge button {
  min-height: 44px; padding: 0.55rem 0.9rem; border-radius: 8px;
  border: 1px solid var(--border); background: #fff; font: inherit; cursor: pointer;
}
.challenge button.clear-btn { background: #1a7a4c; color: #fff; border-color: #1a7a4c; }
.challenge button:disabled { opacity: 0.55; cursor: default; }
.challenge .status { font-size: 0.85rem; margin-top: 6px; }
.challenge .status.ok { color: var(--accent); font-weight: 600; }
.subject-block { margin: 1.25rem 0; }
.subject-block > h2 { font-size: 1.05rem; border-bottom: 1px solid var(--border); padding-bottom: 4px; }
.target {
  background: #fff; border: 1px solid var(--border); border-radius: 12px;
  padding: 14px; margin: 12px 0;
}
.target .reteach { color: #43574c; }
.target details { margin-top: 6px; }
video { width: 100%; max-width: 480px; border-radius: 12px; background: #000; }
.footer-note {
  margin-top: 2rem; padding-top: 1rem; border-top: 1px solid var(--border);
  font-size: 0.8rem; color: var(--muted);
}

/* Racing energy-gated unlock — visible icon + progress */
.racing-unlock .racing-section-title { margin-bottom: 0.25rem; }
.racing-unlock .racing-section-blurb { margin-top: 0; }
.racing-hero {
  display: flex;
  gap: 0.85rem;
  align-items: center;
  margin: 0.75rem 0 0.5rem;
}
.racing-icon {
  flex: 0 0 auto;
  width: 96px;
  height: 96px;
  border-radius: 14px;
  overflow: hidden;
  border: 2px solid var(--border);
  background: #0b0c0e;
  display: grid;
  place-items: center;
}
.racing-icon-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.racing-icon-fallback {
  font-size: 2.5rem;
  background: linear-gradient(145deg, #1a1f27, #2a3340);
  color: #7ddea5;
  border-color: #3a4450;
}
.racing-hero-text { flex: 1; min-width: 0; }
.racing-game-title {
  margin: 0 0 0.35rem;
  font-size: 1.1rem;
  letter-spacing: 0.01em;
}
.racing-progress-text {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
  color: var(--ink, #1a1f1c);
}
.racing-progress-n { color: var(--accent, #2d6a4f); }
.racing-learner { margin: 0.25rem 0 0; font-size: 0.85rem; }
.racing-progress-bar {
  position: relative;
  height: 14px;
  border-radius: 999px;
  background: #e6ebe8;
  border: 1px solid var(--border);
  overflow: hidden;
  margin: 0.35rem 0 0.75rem;
}
.racing-progress-fill {
  height: 100%;
  width: 0;
  border-radius: inherit;
  background: linear-gradient(90deg, #c9a227, #e0c56a);
  transition: width 0.35s ease;
}
.racing-progress-fill.is-complete {
  background: linear-gradient(90deg, #2d6a4f, #52b788);
}
.racing-unlock .racing-meta { display: grid; gap: 0.25rem; margin: 0.5rem 0; }
.racing-unlock .racing-cost,
.racing-unlock .racing-balance { margin: 0; font-size: 0.95rem; }
.racing-unlock.racing-locked {
  border-color: #c9a227;
  background: #fffdf5;
}
.racing-unlock.racing-unlocked {
  border-color: var(--accent);
  background: #f3faf5;
}
.racing-gate {
  margin: 0.75rem 0;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px dashed var(--border);
}
.racing-gate.locked {
  background: #fff8e6;
  border-color: #e0c56a;
}
.racing-gate.unlocked {
  background: #e8f3ec;
  border-color: #8fbf9a;
}
.racing-gate .status.locked-msg { color: #7a5b00; font-weight: 600; }
.racing-actions { margin-top: 0.5rem; }
.racing-play[disabled],
button.racing-play:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}
a.racing-play {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.racing-debit-note,
.racing-url-tbd { margin-top: 0.5rem; }
@media (max-width: 480px) {
  .racing-hero { flex-direction: row; }
  .racing-icon { width: 72px; height: 72px; }
  .racing-progress-text { font-size: 1.15rem; }
}