:root {
  color-scheme: light dark;
  --background: #f3f6fb;
  --surface: #ffffff;
  --text: #101a3d;
  --muted: #5d6988;
  --primary: #0967d8;
  --border: #dce3f0;
}

* {
  box-sizing: border-box;
}

html {
  background: var(--background);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  line-height: 1.6;
}

body {
  color: var(--text);
  margin: 0;
}

header {
  background: color-mix(in srgb, var(--surface) 94%, transparent);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 1;
}

nav {
  align-items: center;
  display: flex;
  gap: 1.25rem;
  justify-content: space-between;
  margin: 0 auto;
  max-width: 860px;
  padding: 1rem 1.5rem;
}

.brand {
  color: var(--text);
  font-size: 1.05rem;
  font-weight: 800;
  text-decoration: none;
}

.links {
  display: flex;
  gap: 1rem;
}

.links a,
footer a {
  color: var(--primary);
  font-weight: 650;
  text-decoration: none;
}

.links a[aria-current="page"] {
  text-decoration: underline;
  text-underline-offset: 0.3rem;
}

main {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 1.25rem;
  box-shadow: 0 10px 40px rgb(16 32 74 / 8%);
  margin: 3rem auto;
  max-width: 860px;
  padding: clamp(1.5rem, 5vw, 4rem);
}

h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin: 0;
}

h2 {
  font-size: 1.3rem;
  line-height: 1.3;
  margin: 2.25rem 0 0.75rem;
}

p,
li {
  font-size: 1rem;
}

.effective {
  color: var(--muted);
  margin: 0.5rem 0 1.75rem;
}

.summary {
  font-size: 1.08rem;
}

li + li {
  margin-top: 0.45rem;
}

footer {
  color: var(--muted);
  margin: 0 auto;
  max-width: 860px;
  padding: 0 1.5rem 3rem;
  text-align: center;
}

@media (max-width: 700px) {
  header {
    position: static;
  }

  nav {
    align-items: flex-start;
    flex-direction: column;
  }

  main {
    border-left: 0;
    border-radius: 0;
    border-right: 0;
    margin: 1rem 0 2rem;
  }
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #081124;
    --surface: #111d36;
    --text: #f2f6ff;
    --muted: #b2bfda;
    --primary: #80b7ff;
    --border: #293754;
  }
}