:root {
  --ink: #0f172a;
  --body: #475569;
  --muted: #94a3b8;
  --line: #e2e8f0;
  --bg: #f8fafc;
  --card: #ffffff;
  --accent: #4648d4;
  --todo-bg: #fff7ed;
  --todo-line: #fcd34d;
  --todo-ink: #b45309;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--body);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

header.site {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  padding: 16px 20px;
}
header.site .wrap { max-width: 820px; margin: 0 auto; display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }
header.site a.brand { font-weight: 800; font-size: 19px; color: var(--ink); text-decoration: none; letter-spacing: -0.3px; }
header.site nav { margin-left: auto; display: flex; gap: 16px; flex-wrap: wrap; }
header.site nav a { color: var(--body); text-decoration: none; font-size: 14px; font-weight: 600; }
header.site nav a:hover { color: var(--accent); }

main { max-width: 820px; margin: 0 auto; padding: 36px 20px 72px; }

h1 { font-size: 32px; line-height: 1.2; color: var(--ink); letter-spacing: -0.6px; margin: 0 0 8px; font-weight: 800; }
h2 { font-size: 20px; color: var(--ink); margin: 32px 0 8px; font-weight: 700; letter-spacing: -0.2px; }
h3 { font-size: 16px; color: var(--ink); margin: 20px 0 6px; font-weight: 700; }
p { margin: 0 0 14px; }
ul, ol { margin: 0 0 14px; padding-left: 22px; }
li { margin-bottom: 6px; }
a { color: var(--accent); }

.lede { font-size: 17px; color: var(--body); margin-bottom: 28px; }
.updated { font-size: 13px; color: var(--muted); margin-bottom: 28px; }

.todo {
  background: var(--todo-bg);
  border: 1px solid var(--todo-line);
  border-left-width: 4px;
  border-radius: 8px;
  padding: 10px 14px;
  margin: 0 0 18px;
  color: var(--todo-ink);
  font-size: 14px;
}
.todo strong { font-weight: 800; }

.card { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 24px; margin-bottom: 20px; }

footer.site { border-top: 1px solid var(--line); background: var(--card); padding: 22px 20px; }
footer.site .wrap { max-width: 820px; margin: 0 auto; font-size: 13px; color: var(--muted); }
footer.site a { color: var(--body); }

@media (max-width: 600px) {
  h1 { font-size: 26px; }
  header.site nav { width: 100%; margin-left: 0; gap: 12px; }
}