body {
    font-family: sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #f0f2f5;
    margin: 0;
    transition: background-color 0.3s ease;
}

body.dark {
    background-color: #1a1a2e;
}

.container {
    text-align: center;
    background-color: white;
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
    transition: background-color 0.3s ease, box-shadow 0.3s ease;
}

body.dark .container {
    background-color: #16213e;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.4);
}

h1 {
    margin-bottom: 30px;
    color: #333;
    transition: color 0.3s ease;
}

body.dark h1 {
    color: #e0e0e0;
}

.numbers-container {
    display: flex;
    justify-content: center;
    gap: 10px;
    margin-bottom: 30px;
}

#generate-btn {
    padding: 15px 30px;
    font-size: 18px;
    color: white;
    background-color: #007bff;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

#generate-btn:hover {
    background-color: #0056b3;
}

#theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 10px 18px;
    font-size: 14px;
    background-color: #333;
    color: white;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    transition: background-color 0.3s ease;
    z-index: 100;
}

#theme-toggle:hover {
    background-color: #555;
}

body.dark #theme-toggle {
    background-color: #f0f2f5;
    color: #333;
}

body.dark #theme-toggle:hover {
    background-color: #d0d2d5;
}