:root {
  --bg: #ffffff;
  --fg: #1a1a1a;
  --muted: #666;
  --accent: #2563eb;
  --border: #e5e7eb;
  --max-width: 720px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --fg: #e6e6e6;
    --muted: #9aa0a6;
    --accent: #60a5fa;
    --border: #262a31;
  }
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

header {
  border-bottom: 1px solid var(--border);
}

nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-weight: 700;
  color: var(--fg);
  font-size: 1.1rem;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 1.25rem;
  margin: 0;
  padding: 0;
}

main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.25rem;
}

.hero {
  padding: 3rem 0;
  border-bottom: 1px solid var(--border);
}

.hero h1 {
  font-size: 2.5rem;
  margin: 0 0 0.5rem;
}

.hero p {
  font-size: 1.15rem;
  color: var(--muted);
  margin: 0;
}

section {
  padding: 2rem 0;
}

section + section {
  border-top: 1px solid var(--border);
}

h2 {
  font-size: 1.5rem;
  margin: 0 0 0.75rem;
}

footer {
  border-top: 1px solid var(--border);
  margin-top: 2rem;
}

footer p {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.5rem 1.25rem;
  color: var(--muted);
  font-size: 0.9rem;
}