:root {
  --bg-color: #f0f2f5;
  --text-color: #333;
  --card-bg: #f9f9f9;
  --number-bg: #fff;
  --number-border: #ddd;
  --primary-color: #007bff;
  --primary-hover: #0056b3;
  --shadow: rgba(0, 0, 0, 0.1);
  --transition: all 0.3s ease;
}

body.dark-mode {
  --bg-color: #121212;
  --text-color: #e0e0e0;
  --card-bg: #1e1e1e;
  --number-bg: #2d2d2d;
  --number-border: #444;
  --primary-color: #3700b3;
  --primary-hover: #1f0064;
  --shadow: rgba(0, 0, 0, 0.5);
}

@media (prefers-color-scheme: dark) {
  body:not(.light-mode) {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --card-bg: #1e1e1e;
    --number-bg: #2d2d2d;
    --number-border: #444;
    --primary-color: #3700b3;
    --primary-hover: #1f0064;
    --shadow: rgba(0, 0, 0, 0.5);
  }
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol';
  background-color: var(--bg-color);
  color: var(--text-color);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  transition: var(--transition);
}

header {
  position: fixed;
  top: 0;
  right: 0;
  padding: 1rem;
}