:root {
  --background-color: #f0f0f0;
  --container-bg-color: #fff;
  --text-color: #000;
  --lotto-number-bg-color: #eee;
  --button-bg-color: #4CAF50;
  --button-text-color: white;
}

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);
  transition: background-color 0.3s, color 0.3s;
}

body.dark-mode {
  --background-color: #333;
  --container-bg-color: #444;
  --text-color: #fff;
  --lotto-number-bg-color: #555;
  --button-bg-color: #5cb85c;
  --button-text-color: white;
}

.container {
  text-align: center;
  background-color: var(--container-bg-color);
  padding: 2rem;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  transition: background-color 0.3s;
}

.lotto-numbers {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin: 2rem 0;
}

.lotto-number {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background-color: var(--lotto-number-bg-color);
  font-size: 1.5rem;
  font-weight: bold;
  transition: background-color 0.3s, transform 0.3s ease-out, opacity 0.3s ease-out;
  opacity: 0;
  transform: scale(0.5);
}

.lotto-number.revealed {
  opacity: 1;
  transform: scale(1);
}

#generate-btn, #theme-toggle-btn {
  padding: 0.8rem 1.5rem;
  font-size: 1rem;
  border: none;
  border-radius: 5px;
  background-color: var(--button-bg-color);
  color: var(--button-text-color);
  cursor: pointer;
  transition: background-color 0.3s;
}

#theme-toggle-btn {
  margin-bottom: 1rem;
}