:root {
  color-scheme: light dark;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, #1e293b, #0f172a);
  color: #e2e8f0;
}
.container {
  text-align: center;
  padding: 2rem;
}
h1 { font-size: 2.4rem; margin: 0 0 .3rem; }
.subtitle { color: #94a3b8; margin: 0 0 1.5rem; }
.counter-btn {
  font-size: 1.1rem;
  padding: .8rem 1.6rem;
  border: none;
  border-radius: 10px;
  background: #6366f1;
  color: white;
  cursor: pointer;
  transition: transform .1s, background .2s;
}
.counter-btn:hover { background: #4f46e5; }
.counter-btn:active { transform: scale(.97); }
.counter-btn strong { font-variant-numeric: tabular-nums; }
.hint { margin-top: 1.5rem; color: #64748b; font-size: .85rem; }