:root {
  /* Light Mode Variables */
  --bg-color: #f7f7f7;
  --text-color: #333;
  --card-bg: #ffffff;
  --card-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
  --button-bg: #007bff;
  --button-hover: #0056b3;
  --button-text: #ffffff;
  --number-bg: #f0f0f0;
  --number-text: #333;
  --transition-speed: 0.3s;
}

body.dark-mode {
  /* Dark Mode Variables */
  --bg-color: #121212;
  --text-color: #e0e0e0;
  --card-bg: #1e1e1e;
  --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
  --button-bg: #3700b3;
  --button-hover: #6200ee;
  --button-text: #ffffff;
  --number-bg: #2c2c2c;
  --number-text: #e0e0e0;
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  margin: 0;
  background-color: var(--bg-color);
  color: var(--text-color);
  transition: background-color var(--transition-speed), color var(--transition-speed);
}

h1 {
  margin-bottom: 1rem;
  font-weight: 300;
  letter-spacing: 1px;
}

.controls {
  position: fixed;
  top: 20px;
  right: 20px;
}