:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --text: #16191f;
  --muted: #5c6470;
  --accent: #1a6d5a;
  --border: #e2e5ea;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 2rem 1rem;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.55;
  color: var(--text);
  background: var(--bg);
}

.header,
.main,
.footer {
  max-width: 44rem;
  margin: 0 auto;
}

.header h1 {
  margin: 0 0 0.25rem;
  font-size: 2rem;
}

.tagline {
  margin: 0 0 2rem;
  color: var(--muted);
}

.card {
  padding: 1.25rem 1.5rem;
  margin-bottom: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
}

.card h2 {
  margin: 0 0 0.5rem;
  font-size: 1.125rem;
}

.card p {
  margin: 0 0 0.75rem;
}

code {
  padding: 0.1em 0.35em;
  font-size: 0.9em;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 4px;
}

output {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
}

button {
  padding: 0.5rem 1rem;
  font: inherit;
  color: #fff;
  background: var(--accent);
  border: 0;
  border-radius: 6px;
  cursor: pointer;
}

button:hover {
  filter: brightness(1.1);
}

button:focus-visible {
  outline: 2px solid var(--text);
  outline-offset: 2px;
}

.footer {
  margin-top: 2rem;
  color: var(--muted);
  font-size: 0.875rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171c;
    --surface: #1c2027;
    --text: #eef1f5;
    --muted: #9aa3b0;
    --accent: #2f9e83;
    --border: #2b313a;
  }
}