:root {
  --bg: #ffffff;
  --surface: #f4f4fb;
  --text: #1c1b22;
  --muted: #5b5a66;
  --accent: #3f51b5;
  --border: #e2e1ec;
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121218;
    --surface: #1c1c25;
    --text: #e6e5ee;
    --muted: #a9a8b6;
    --accent: #9fa8ff;
    --border: #2c2c38;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 17px;
  line-height: 1.6;
}

header,
main,
footer {
  max-width: 680px;
  margin: 0 auto;
  padding: 0 16px;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 24px;
  padding-bottom: 24px;
}

header .brand {
  font-weight: 700;
  font-size: 20px;
  color: var(--text);
  text-decoration: none;
}

nav {
  display: flex;
  gap: 16px;
}

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

nav a {
  text-decoration: none;
}

nav a:hover,
nav a:focus-visible {
  text-decoration: underline;
}

main {
  padding-bottom: 48px;
}

h1 {
  font-size: 32px;
  line-height: 1.2;
  margin: 16px 0 8px;
}

h2 {
  font-size: 21px;
  margin: 32px 0 8px;
}

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

h3 + p {
  margin-top: 0;
}

.muted {
  color: var(--muted);
}

.hero {
  padding: 48px 0 16px;
}

.hero h1 {
  font-size: 44px;
}

.hero .tagline {
  font-size: 21px;
  color: var(--muted);
  margin: 0 0 24px;
}

.summary {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 20px;
}

.summary p {
  margin: 0;
}

footer {
  border-top: 1px solid var(--border);
  padding-top: 16px;
  padding-bottom: 32px;
  font-size: 15px;
  color: var(--muted);
}

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