:root {
  --bg: #0f172a;          /* slate-900 */
  --panel: #111827;       /* gray-900 */
  --text: #e5e7eb;        /* gray-200 */
  --muted: #9ca3af;       /* gray-400 */
  --accent: #22d3ee;      /* cyan-400 */
}

* { box-sizing: border-box; }

html, body {
  height: 100%;
  margin: 0;
  background: radial-gradient(1200px 600px at 20% 10%, #111827 0%, var(--bg) 60%);
  color: var(--text);
  font: 16px/1.6 system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, sans-serif;
}

.container {
  max-width: 720px;
  margin: 8vh auto;
  padding: 0 16px;
}

h1 {
  font-size: 2.25rem;
  margin: 0 0 8px;
}

h2 { margin: 16px 0 8px; }

.card {
  margin-top: 16px;
  padding: 16px 18px;
  background: linear-gradient(180deg, rgba(255,255,255,0.04), rgba(255,255,255,0.02));
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.35);
}

code {
  background: rgba(255,255,255,0.08);
  padding: 2px 6px;
  border-radius: 6px;
}

button {
  margin-top: 8px;
  padding: 10px 14px;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,0.16);
  background: transparent;
  color: var(--text);
  cursor: pointer;
  transition: transform 0.05s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
button:hover {
  border-color: var(--accent);
  box-shadow: 0 6px 22px rgba(34,211,238,0.25);
}
button:active { transform: translateY(1px); }

.muted { color: var(--muted); }