:root {
  --background-color: #f0f0f0;
  --text-color: #333;
  --container-bg: #ffffff;
  --number-bg: #ffffff;
  --number-border: #ccc;
  --button-bg: #007bff;
  --button-hover-bg: #0056b3;
}

body.dark-mode {
  --background-color: #333;
  --text-color: #f0f0f0;
  --container-bg: #444;
  --number-bg: #555;
  --number-border: #888;
  --button-bg: #0056b3;
  --button-hover-bg: #007bff;
}

body {
  font-family: sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background-color: var(--background-color);
  color: var(--text-color);
}

.container {
  text-align: center;
  background-color: var(--container-bg);
  padding: 2rem;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
}

h1 {
  margin-bottom: 2rem;
}

.numbers-container {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
}

.number {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: var(--number-bg);
  border: 2px solid var(--number-border);
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.5rem;
  font-weight: bold;
}

#generate-btn {
  padding: 1rem 2rem;
  font-size: 1rem;
  border: none;
  border-radius: 5px;
  background-color: var(--button-bg);
  color: #fff;
  cursor: pointer;
  transition: background-color 0.3s;
}

#generate-btn:hover {
  background-color: var(--button-hover-bg);
}