:root {
  --bg: #f7f7f5;
  --surface: #ffffff;
  --text: #1c1c1e;
  --muted: #6b6b70;
  --border: #e4e4e0;
  --accent: #1f8a5b;
  --accent-text: #ffffff;
  --todo-bg: #fff6d6;
  --todo-border: #e8c84a;
  --radius: 14px;
  --max: 720px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111113;
    --surface: #1c1c1f;
    --text: #f2f2f4;
    --muted: #9a9aa2;
    --border: #2c2c31;
    --accent: #3ccf8e;
    --accent-text: #0b2a1c;
    --todo-bg: #2e2810;
    --todo-border: #8a7420;
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 17px/1.6 -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, sans-serif;
}

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

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 16px;
}

header.site {
  border-bottom: 1px solid var(--border);
  background: var(--surface);
}

header.site .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 19px;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.brand img { width: 28px; height: 28px; }

nav.top a {
  color: var(--muted);
  text-decoration: none;
  font-size: 15px;
  margin-left: 16px;
}

nav.top a:hover { color: var(--text); }

main { padding: 40px 0 64px; }

h1 {
  font-size: 32px;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: 0 0 12px;
}

h2 {
  font-size: 21px;
  margin: 36px 0 8px;
  letter-spacing: -0.01em;
}

h3 { font-size: 17px; margin: 24px 0 4px; }

p, li { color: var(--text); }

.lead { font-size: 19px; color: var(--muted); margin-bottom: 28px; }

.meta { color: var(--muted); font-size: 14px; }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin: 24px 0;
}

.button {
  display: inline-block;
  background: var(--accent);
  color: var(--accent-text);
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 600;
  text-decoration: none;
}

.todo {
  background: var(--todo-bg);
  border: 1px dashed var(--todo-border);
  border-radius: 10px;
  padding: 12px 16px;
  margin: 12px 0;
  font-size: 15px;
}

.todo::before { content: "TODO · "; font-weight: 700; }

.hero { text-align: center; padding: 32px 0 8px; }

.hero img { width: 72px; height: 72px; margin-bottom: 16px; }

.features {
  display: grid;
  gap: 12px;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  margin: 32px 0;
}

.features .card { margin: 0; }

.features h3 { margin-top: 0; }

footer.site {
  border-top: 1px solid var(--border);
  padding: 24px 0 40px;
  font-size: 14px;
  color: var(--muted);
}

footer.site a {
  color: var(--muted);
  margin-right: 16px;
  text-decoration: none;
}

footer.site a:hover { color: var(--text); }

@media (max-width: 480px) {
  h1 { font-size: 27px; }
  nav.top a { margin-left: 12px; font-size: 14px; }
}