:root {
  --bg: #0e0f13;
  --surface: #171920;
  --border: #262a35;
  --text: #eceef3;
  --muted: #8b90a0;
  --accent: #7c9cff;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f5f6fa;
    --surface: #fff;
    --border: #dfe2ec;
    --text: #15171d;
    --muted: #6a7080;
    --accent: #3b5bdb;
  }
}

* { box-sizing: border-box; margin: 0; }

body {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px 16px;
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
}

.hub { width: 100%; max-width: 720px; }

header { text-align: center; margin-bottom: 40px; }
h1 { font-size: clamp(2rem, 6vw, 3rem); letter-spacing: -0.03em; }
h1 span { color: var(--accent); }
header p { color: var(--muted); margin-top: 8px; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 16px;
}

.card {
  position: relative;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  color: inherit;
  text-decoration: none;
  transition: transform .15s ease, border-color .15s ease;
}

.card:hover,
.card:focus-visible {
  transform: translateY(-3px);
  border-color: var(--accent);
  outline: none;
}

.card h2 { font-size: 1.15rem; margin-bottom: 4px; }
.card p { color: var(--muted); font-size: .9rem; }

.key {
  position: absolute;
  top: 14px;
  right: 14px;
  width: 22px;
  height: 22px;
  display: grid;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--muted);
  font-size: .75rem;
}

@media (hover: none) { .key { display: none; } }
@media (prefers-reduced-motion: reduce) { .card { transition: none; } }