:root {
  --bg-start: #0ea5e9;
  --bg-end: #14b8a6;
  --card-bg: #ffffff;
  --text: #1f2937;
  --accent: #0d9488;
}

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

body {
  min-height: 100vh;
  display: grid;
  place-items: center;
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  background: linear-gradient(135deg, var(--bg-start), var(--bg-end));
  color: var(--text);
  padding: 1rem;
}

.card {
  background: var(--card-bg);
  padding: 2.5rem 3rem;
  border-radius: 1rem;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.25);
  text-align: center;
  max-width: 30rem;
}

h1 {
  font-size: 1.9rem;
  margin-bottom: 0.75rem;
}

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

.tagline {
  color: #6b7280;
  margin-bottom: 1.75rem;
  line-height: 1.5;
}

.btn {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: transform 0.05s ease, background 0.2s ease;
}

.btn:hover {
  background: #4f46e5;
}

.btn:active {
  transform: scale(0.96);
}

.counter {
  margin-top: 1rem;
  color: #374151;
}

.clock {
  margin-top: 1.5rem;
  font-variant-numeric: tabular-nums;
  font-size: 1.25rem;
  color: #9ca3af;
}