:root {
  color-scheme: dark;
  --lesson-cream: #fff8dd;
  --lesson-ink: #17352d;
  --lesson-green: #55d98c;
  --lesson-green-dark: #183e31;
  --lesson-gold: #ffd866;
}

body {
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(circle at 16% 15%, rgba(85, 217, 140, .14), transparent 28rem),
    radial-gradient(circle at 88% 80%, rgba(255, 216, 102, .1), transparent 24rem),
    #091713;
  color: var(--lesson-cream);
}

.lesson-topbar {
  min-height: 64px;
  padding: 10px clamp(16px, 4vw, 48px);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-bottom: 1px solid rgba(255, 255, 255, .12);
  background: rgba(9, 23, 19, .9);
}

.home-link, .privacy-chip { color: var(--lesson-cream); }
.home-link { min-height: 44px; display: inline-flex; align-items: center; font-weight: 800; }
.privacy-chip { font-size: .85rem; opacity: .8; }

.lesson-page {
  width: min(760px, calc(100% - 32px));
  margin: 0 auto;
  padding: clamp(28px, 6vw, 72px) 0;
}

.lesson-card {
  padding: clamp(24px, 5vw, 52px);
  border: 1px solid rgba(85, 217, 140, .35);
  border-radius: 24px;
  background: linear-gradient(145deg, rgba(27, 62, 50, .98), rgba(13, 35, 29, .98));
  box-shadow: 0 24px 80px rgba(0, 0, 0, .32);
}

.eyebrow { margin: 0 0 8px; color: var(--lesson-green); font-weight: 900; letter-spacing: .08em; text-transform: uppercase; font-size: .78rem; }
h1 { margin: 0; font-size: clamp(2rem, 7vw, 3.5rem); line-height: 1.05; }
h2 { margin: 0 0 12px; font-size: 1.2rem; }
.lead { max-width: 62ch; color: rgba(255, 248, 221, .82); line-height: 1.6; }

.field-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; margin: 28px 0; }
.lesson-selection-summary { margin: -10px 0 20px; padding: 14px 16px; color: rgba(255, 248, 221, .88); background: rgba(0, 0, 0, .2); border-left: 4px solid var(--lesson-gold); border-radius: 10px; line-height: 1.5; }
label { display: grid; gap: 8px; font-weight: 800; }
select, input, button, .button-link {
  min-height: 48px;
  border: 2px solid rgba(255, 255, 255, .25);
  border-radius: 12px;
  padding: 10px 14px;
  font: inherit;
}
select, input { width: 100%; box-sizing: border-box; color: var(--lesson-ink); background: var(--lesson-cream); }
button, .button-link { cursor: pointer; font-weight: 900; text-decoration: none; color: var(--lesson-cream); background: var(--lesson-green-dark); }
.primary-action { border-color: var(--lesson-green); color: #082218; background: var(--lesson-green); }
button:hover, .button-link:hover { filter: brightness(1.1); }
button:focus-visible, .button-link:focus-visible, select:focus-visible, input:focus-visible, .home-link:focus-visible { outline: 4px solid var(--lesson-gold); outline-offset: 3px; }

.link-result, .guidance, .learning-goals { margin-top: 28px; padding: 20px; border-radius: 16px; background: rgba(0, 0, 0, .2); }
.result-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 16px; }
.status { min-height: 1.5em; margin-bottom: 0; color: var(--lesson-green); font-weight: 800; }

.invitation { text-align: center; }
.nature-mark { margin-bottom: 12px; font-size: 3rem; }
.game-name { color: var(--lesson-green); font-size: 1.25rem; font-weight: 900; }
.math-fit { margin: -10px 0 0; color: var(--lesson-gold); font-weight: 850; }
.learning-goals { text-align: left; border-left: 4px solid var(--lesson-green); }
.learning-goals h2 { color: var(--lesson-green); }
.learning-goals ul { margin: 0; padding-left: 1.25rem; line-height: 1.5; }
.learning-goals li + li { margin-top: 8px; }
.mission-details { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin: 28px 0; text-align: left; }
.mission-details div { padding: 16px; border-radius: 14px; background: rgba(0, 0, 0, .2); }
.mission-details dt { color: rgba(255, 248, 221, .7); font-size: .8rem; font-weight: 800; text-transform: uppercase; }
.mission-details dd { margin: 6px 0 0; font-weight: 900; }
.guidance { text-align: left; }
.guidance li + li { margin-top: 8px; }
.launch-note, .privacy-note { line-height: 1.5; }
.privacy-note { margin: 22px 0 0; font-size: .85rem; opacity: .72; }

[hidden] { display: none !important; }

@media (max-width: 620px) {
  .field-grid, .mission-details { grid-template-columns: 1fr; }
  .privacy-chip { display: none; }
  .lesson-page { width: min(100% - 20px, 760px); padding-top: 18px; }
  .lesson-card { border-radius: 18px; }
  .result-actions > * { width: 100%; box-sizing: border-box; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition: none !important; animation: none !important; }
}