:root {
  color-scheme: light dark;
  --bg: #f4f6f4;
  --fg: #1d2a22;
  --accent: #1f5f3a;
  --muted: #5b6b61;
  --card: #ffffff;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111814;
    --fg: #e6ece8;
    --accent: #8fd3a8;
    --muted: #a3b2a9;
    --card: #1a231d;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, -apple-system, "Segoe UI", "Hiragino Sans", "Noto Sans JP", Meiryo, sans-serif;
  line-height: 1.6;
}

.site-header, main, .site-footer {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 1rem;
}

.site-header { padding-top: 1.25rem; }
.site-header h1 { margin: 0 0 0.25rem; font-size: 1.75rem; }
.lead { margin: 0 0 1rem; color: var(--muted); }

.game-frame {
  width: 100%;
  aspect-ratio: 16 / 10;
  max-height: 85vh;
  min-height: 420px;
  background: var(--accent);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.25);
}

.game-frame iframe {
  display: block;
  width: 100%;
  height: 100%;
  border: 0;
}

.hint { margin: 0.5rem 0 1.5rem; color: var(--muted); font-size: 0.9rem; }

.help {
  background: var(--card);
  border-radius: 8px;
  padding: 1rem 1.25rem;
  margin-bottom: 1.5rem;
}

.help h2 { margin-top: 0; font-size: 1.25rem; }
.help ul { margin: 0; padding-left: 1.25rem; }
.help li { margin: 0.35rem 0; }

kbd {
  display: inline-block;
  padding: 0 0.4em;
  border: 1px solid var(--muted);
  border-bottom-width: 2px;
  border-radius: 4px;
  font-family: ui-monospace, Consolas, monospace;
  font-size: 0.9em;
  background: var(--bg);
}

code { font-family: ui-monospace, Consolas, monospace; }

a { color: var(--accent); }

.site-footer { padding-bottom: 2rem; color: var(--muted); font-size: 0.9rem; }

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

@media (max-width: 600px) {
  .game-frame { aspect-ratio: 3 / 4; min-height: 360px; }
}