:root {
  color-scheme: dark;
  --bg: #080b0f;
  --surface: #101821;
  --line: rgba(205, 229, 238, 0.16);
  --text: #f3f7f8;
  --muted: #9fb0b8;
  --cyan: #4ed9dd;
  --amber: #ffbd5a;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 12% 4%, rgba(78, 217, 221, 0.12), transparent 30%),
    linear-gradient(180deg, #080b0f 0%, #0a0e12 100%);
  color: var(--text);
}

main {
  width: min(850px, calc(100% - 36px));
  margin: 0 auto;
  padding: 40px 0 70px;
}

header,
section,
footer {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(16, 24, 33, 0.68);
}

header {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: center;
  padding: 18px;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 12px 16px;
}

a {
  color: var(--cyan);
  text-decoration: none;
  font-weight: 760;
}

.brand {
  color: var(--text);
  font-size: 18px;
  font-weight: 820;
}

section {
  margin-top: 18px;
  padding: 26px;
}

h1 {
  margin: 0;
  font-size: clamp(34px, 5vw, 56px);
  line-height: 1;
}

h2 {
  margin: 30px 0 10px;
  color: var(--amber);
  font-size: 18px;
}

p,
li {
  color: var(--muted);
  font-size: 16px;
  line-height: 1.65;
}

ul {
  padding-left: 20px;
}

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

footer {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 18px;
  padding: 18px;
  color: var(--muted);
}

@media (max-width: 640px) {
  header,
  footer {
    display: grid;
  }

  .site-nav {
    justify-content: flex-start;
  }

  section {
    padding: 20px;
  }
}