:root {
    --background-color: #f0f0f0;
    --text-color: #333;
    --container-bg-color: #fff;
    --button-bg-color: #007bff;
    --button-text-color: #fff;
}

body.dark-theme {
    --background-color: #333;
    --text-color: #f0f0f0;
    --container-bg-color: #555;
    --button-bg-color: #28a745;
    --button-text-color: #fff;
}

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;
}

.container {
    text-align: center;
    background-color: var(--container-bg-color);
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s, box-shadow 0.3s;
}

#generate-btn, #theme-toggle-btn {
    padding: 10px 20px;
    font-size: 16px;
    cursor: pointer;
    margin: 10px;
    background-color: var(--button-bg-color);
    color: var(--button-text-color);
    border: none;
    border-radius: 5px;
    transition: background-color 0.3s, color 0.3s;
}

#numbers-container {
    display: flex;
    gap: 10px;
}

.number {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 20px;
    font-weight: bold;
    color: white;
}