:root {
  --background-color-light: #f0f0f0;
  --text-color-light: #333;
  --number-bg-color-light: #fff;
  --number-border-color-light: #333;
  --button-bg-color-light: #fff;
  --button-text-color-light: #333;
}

.dark-mode {
  --background-color-dark: #333;
  --text-color-dark: #f0f0f0;
  --number-bg-color-dark: #555;
  --number-border-color-dark: #f0f0f0;
  --button-bg-color-dark: #555;
  --button-text-color-dark: #f0f0f0;
}

body {
  font-family: sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background-color: var(--background-color-light);
  color: var(--text-color-light);
  transition: background-color 0.3s, color 0.3s;
}

.dark-mode body {
  background-color: var(--background-color-dark);
  color: var(--text-color-dark);
}

.container {
  text-align: center;
}

.numbers {
  display: flex;
  margin-bottom: 20px;
}

.number {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: var(--number-bg-color-light);
  border: 2px solid var(--number-border-color-light);
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 24px;
  margin: 0 5px;
  color: var(--text-color-light);
}

.dark-mode .number {
  background-color: var(--number-bg-color-dark);
  border-color: var(--number-border-color-dark);
  color: var(--text-color-dark);
}

#generate, #theme-toggle {
  padding: 10px 20px;
  font-size: 18px;
  cursor: pointer;
  background-color: var(--button-bg-color-light);
  color: var(--button-text-color-light);
  border: 1px solid var(--text-color-light);
}

.dark-mode #generate, .dark-mode #theme-toggle {
  background-color: var(--button-bg-color-dark);
  color: var(--button-text-color-dark);
  border: 1px solid var(--text-color-dark);
}