:root {
  --background-color: #f0f0f0;
  --text-color: #333;
  --button-background: #007bff;
  --button-text: #fff;
  --container-background: #f0f0f0;
  --number-background: #fff;
  --number-border: #ccc;
  --additional-number-border: #f00;
  --shadow-color: rgba(0, 0, 0, 0.1);
}

body.night-mode {
  --background-color: #333;
  --text-color: #f0f0f0;
  --button-background: #555;
  --button-text: #fff;
  --container-background: #444;
  --number-background: #555;
  --number-border: #888;
  --additional-number-border: #ff5555;
  --shadow-color: rgba(0, 0, 0, 0.4);
}

body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  margin: 0;
  background-color: var(--background-color);
  color: var(--text-color);
  transition: background-color 0.3s, color 0.3s;
}

#theme-switcher {
  position: absolute;
  top: 1rem;
  right: 1rem;
  padding: 0.5rem 1rem;
  border: none;
  background-color: var(--button-background);
  color: var(--button-text);
  border-radius: 5px;
  cursor: pointer;
}