:root {
  --bg: #fafaf7;
  --fg: #1c1c1e;
  --muted: #6e6e73;
  --accent: #d93a2a;
  --card: #ffffff;
  --border: rgba(0, 0, 0, 0.08);
  --radius: 14px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0c0c0d;
    --fg: #f2f2f7;
    --muted: #98989d;
    --accent: #ff6b5c;
    --card: #1c1c1e;
    --border: rgba(255, 255, 255, 0.08);
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro", "Segoe UI", system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 48px 24px 80px;
}

nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--border);
}

nav a {
  color: var(--fg);
  text-decoration: none;
  margin-right: 20px;
  font-size: 15px;
}

nav a:last-child { margin-right: 0; }
nav a:hover { color: var(--accent); }

nav .brand {
  font-weight: 600;
  font-size: 17px;
  color: var(--accent);
}

h1 {
  font-size: 40px;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin: 48px 0 16px;
  font-weight: 700;
}

h2 {
  font-size: 24px;
  line-height: 1.25;
  letter-spacing: -0.01em;
  margin: 40px 0 12px;
  font-weight: 600;
}

h3 {
  font-size: 19px;
  line-height: 1.3;
  margin: 28px 0 8px;
  font-weight: 600;
}

.lede {
  font-size: 22px;
  line-height: 1.5;
  color: var(--muted);
  margin-bottom: 32px;
}

p { margin-bottom: 16px; }

ul, ol { margin: 0 0 16px 20px; }
li { margin-bottom: 6px; }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 0.15s;
}

a:hover { border-bottom-color: var(--accent); }

code {
  font-family: "SF Mono", ui-monospace, Menlo, monospace;
  background: var(--card);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 14px;
  border: 1px solid var(--border);
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin: 16px 0;
}

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin: 32px 0;
}

.meta {
  color: var(--muted);
  font-size: 14px;
  margin-top: 8px;
}

footer {
  margin-top: 64px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 14px;
  text-align: center;
}

footer a { color: var(--muted); }

.kbd {
  display: inline-block;
  padding: 2px 8px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 6px;
  font-family: "SF Mono", monospace;
  font-size: 13px;
}

details {
  border-bottom: 1px solid var(--border);
  padding: 16px 0;
}

details summary {
  cursor: pointer;
  font-weight: 500;
  padding: 4px 0;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

details summary::after {
  content: "+";
  color: var(--muted);
  font-size: 20px;
}

details[open] summary::after { content: "−"; }

details > *:not(summary) { margin-top: 12px; }

@media (max-width: 480px) {
  .wrap { padding: 32px 20px 60px; }
  h1 { font-size: 32px; }
  h2 { font-size: 21px; }
  .lede { font-size: 19px; }
}