/* ===========================================================================
   LANDING PAGE
   ===========================================================================
   Single-screen hero with:
     - Product name + tagline
     - What it does / how it works (three short cards)
     - Lesson selector
     - Consent + camera permission note
     - Start button (links to app.html?lesson=...)
   =========================================================================== */

.landing {
  min-height: 100vh;
  display: grid;
  grid-template-rows: auto 1fr auto;
  max-width: 1100px;
  margin: 0 auto;
  padding: 48px 48px 24px;
}

/* ---------------- TOP BAR ---------------- */

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 60px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--grid-line);
}
.wordmark {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 400;
  letter-spacing: -0.02em;
}
.wordmark::before {
  content: '◉';
  color: var(--accent);
  margin-right: 10px;
  font-size: 22px;
  vertical-align: 1px;
}
.topbar-links {
  font-size: 12px;
  color: var(--fg-dim);
  letter-spacing: 0.05em;
}
.topbar-links a { margin-left: 20px; }

/* ---------------- HERO ---------------- */

.hero {
  margin-bottom: 60px;
}
.hero-kicker {
  color: var(--accent);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.hero-title {
  font-family: var(--font-display);
  font-size: 64px;
  font-weight: 400;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
  max-width: 820px;
}
.hero-title em {
  font-style: italic;
  color: var(--accent);
}
.hero-subtitle {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 400;
  color: var(--fg-dim);
  max-width: 720px;
  line-height: 1.5;
}

/* ---------------- EXPLAINER CARDS ---------------- */

.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-bottom: 60px;
}
.card {
  background: var(--bg-elevated);
  border: 1px solid var(--grid-line);
  padding: 24px;
  position: relative;
}
.card-num {
  position: absolute;
  top: 16px;
  right: 20px;
  font-size: 10px;
  color: var(--fg-faint);
  letter-spacing: 0.15em;
}
.card-icon {
  font-size: 22px;
  color: var(--accent);
  margin-bottom: 14px;
  font-family: var(--font-display);
}
.card-title {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 600;
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}
.card-body {
  font-size: 13px;
  color: var(--fg-dim);
  line-height: 1.6;
}

/* ---------------- LESSON SELECTOR ---------------- */

.selector-header {
  font-size: 11px;
  color: var(--fg-dim);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  margin-bottom: 16px;
}
.lesson-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 40px;
}
.lesson-option {
  background: var(--bg-brick);
  border: 1px solid var(--grid-line);
  padding: 20px 24px;
  cursor: pointer;
  transition: all 0.15s ease;
  text-align: left;
  color: var(--fg);
  display: block;
  text-decoration: none;
}
.lesson-option:hover {
  border-color: var(--accent-dim);
  background: var(--bg-brick-active);
  text-decoration: none;
}
.lesson-option.selected {
  border-color: var(--accent);
  background: var(--bg-brick-active);
}
.lesson-subject {
  font-size: 10px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}
.lesson-title {
  font-family: var(--font-display);
  font-size: 18px;
  line-height: 1.25;
  color: var(--fg);
}

/* ---------------- CONSENT + START ---------------- */

.consent {
  background: var(--bg-elevated);
  border-left: 2px solid var(--accent);
  padding: 20px 24px;
  margin-bottom: 28px;
  font-size: 13px;
  color: var(--fg-dim);
  line-height: 1.7;
}
.consent strong { color: var(--fg); }

.start-row {
  display: flex;
  gap: 16px;
  align-items: center;
  margin-bottom: 40px;
}
.start-btn {
  background: var(--accent);
  color: #1a1109;
  border: none;
  padding: 16px 40px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  cursor: pointer;
  transition: transform 0.1s ease, box-shadow 0.2s ease;
  font-family: var(--font-ui);
}
.start-btn:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(244, 184, 96, 0.25);
}
.start-btn:disabled {
  background: var(--fg-faint);
  color: var(--bg);
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}
.start-hint {
  font-size: 12px;
  color: var(--fg-faint);
}

/* ---------------- COMPAT WARNING ---------------- */

.compat-warn {
  background: rgba(224, 134, 86, 0.08);
  border: 1px solid var(--warn);
  color: var(--warn);
  padding: 14px 20px;
  margin-bottom: 24px;
  font-size: 13px;
  display: none;
}
.compat-warn.visible { display: block; }

/* ---------------- FOOTER ---------------- */

.footer {
  border-top: 1px solid var(--grid-line);
  padding-top: 24px;
  margin-top: 60px;
  font-size: 12px;
  color: var(--fg-faint);
  display: flex;
  justify-content: space-between;
  letter-spacing: 0.04em;
}

/* ---------------- RESPONSIVE ---------------- */

@media (max-width: 860px) {
  .landing { padding: 32px 24px; }
  .hero-title { font-size: 40px; }
  .hero-subtitle { font-size: 16px; }
  .cards { grid-template-columns: 1fr; }
  .lesson-list { grid-template-columns: 1fr; }
  .start-row { flex-direction: column; align-items: stretch; }
}