:root { --bg: #ffffff; --fg: #1d2420; --muted: #5c6862; --accent: #2e7354; --card: #f3f6f4; }
@media (prefers-color-scheme: dark) {
  :root { --bg: #121614; --fg: #e8eeea; --muted: #a3b0a9; --accent: #7fcfa6; --card: #1c221f; }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); line-height: 1.6;
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "Segoe UI", "Hiragino Sans", "Noto Sans JP", sans-serif; }
header, main, footer { max-width: 760px; margin: 0 auto; padding: 16px; }
header { display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; align-items: center; }
nav { display: flex; flex-wrap: wrap; gap: 14px; }
a { color: var(--accent); }
.brand { font-weight: 700; font-size: 20px; text-decoration: none; color: var(--fg); }
.hero { padding: 48px 0; }
.hero h1 { font-size: clamp(30px, 7vw, 46px); line-height: 1.15; margin: 0 0 12px; }
.hero p { color: var(--muted); font-size: 19px; }
.buttons { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 24px; }
.button { display: inline-block; padding: 12px 18px; border-radius: 12px; background: var(--card); text-decoration: none; font-weight: 600; }
h2 { margin-top: 32px; }
footer { color: var(--muted); font-size: 14px; border-top: 1px solid var(--card); margin-top: 48px; }