:root { --bg: #ffffff; --fg: #1f2937; --card: #f3f4f6; --accent: #2563eb; }
body.dark { --bg: #111827; --fg: #f9fafb; --card: #1f2937; }

* { box-sizing: border-box; }
body {
  margin: 0; font-family: system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  background: var(--bg); color: var(--fg); transition: background .2s, color .2s;
}
header, footer {
  display: flex; justify-content: space-between; align-items: center;
  padding: 1rem 2rem;
}
.logo { font-weight: 700; color: var(--accent); }
button {
  background: var(--accent); color: #fff; border: 0;
  padding: .5rem 1rem; border-radius: 6px; cursor: pointer;
}
main { max-width: 900px; margin: 0 auto; padding: 2rem; }
h1 { font-size: 2.5rem; margin-bottom: .5rem; }
.cards {
  display: grid; gap: 1rem; margin: 2rem 0;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}
.cards article { background: var(--card); padding: 1.25rem; border-radius: 10px; }
.cards h2 { margin-top: 0; color: var(--accent); }
.version { opacity: .7; }
footer { justify-content: center; opacity: .6; font-size: .9rem; }