:root {
  color-scheme: dark;
  --bg: #0f1115;
  --fg: #e6e8ee;
  --muted: #8b90a0;
  --faint: #6b7080;
  --surface: #171a21;
  --border: #232733;
  --accent: #4f7cff;
  --accent-hover: #3d68e6;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--fg);
}

.app { width: min(720px, 92vw); text-align: center; }

h1 { font-weight: 650; letter-spacing: -0.02em; margin: 0 0 0.25rem; }

.sub { color: var(--muted); margin: 0 0 2rem; font-size: 0.95rem; }

.cards {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-bottom: 2rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.4rem 1rem;
  transition: border-color 0.25s;
}

.card.active { border-color: var(--accent); }

.card .label {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.card .value {
  font-size: 2rem;
  font-weight: 680;
  margin: 0.4rem 0 0.1rem;
  font-variant-numeric: tabular-nums;
}

.card .unit { font-size: 0.8rem; color: var(--muted); }

.card .detail {
  font-size: 0.72rem;
  color: var(--faint);
  margin-top: 0.35rem;
  min-height: 1em;
}

button {
  font: inherit;
  font-weight: 600;
  color: #fff;
  background: var(--accent);
  border: 0;
  padding: 0.8rem 2.2rem;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.2s;
}

button:hover:not(:disabled) { background: var(--accent-hover); }

button:disabled { background: #2a2f3b; color: var(--faint); cursor: default; }

.status { margin-top: 1rem; color: var(--muted); font-size: 0.88rem; min-height: 1.2em; }