* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Arial', sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    background: linear-gradient(to right, #ffecd2, #fcb69f);
    margin: 0;
}

.container {
    text-align: center;
    background: white;
    padding: 20px;
    border-radius: 15px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    max-width: 90%;
    width: 400px;
}

h1 {
    font-size: 24px;
    margin-bottom: 20px;
    color: #333;
}

button {
    padding: 10px 20px;
    font-size: 16px;
    margin: 10px 5px;
    cursor: pointer;
    border: none;
    border-radius: 5px;
    transition: background 0.3s;
}

button#generate-btn {
    background: #4CAF50;
    color: white;
}

button#generate-btn:hover {
    background: #45a049;
}

button#copy-btn {
    background: #008CBA;
    color: white;
    display: none;
}

button#copy-btn:hover {
    background: #007BB5;
}

.number {
    display: inline-block;
    margin: 5px;
    width: 40px;
    height: 40px;
    line-height: 40px;
    border-radius: 50%;
    color: white;
    font-weight: bold;
    font-size: 18px;
}

.red-ball {
    background-color: #E74C3C;
}

.blue-ball {
    background-color: #3498DB;
}

@media (max-width: 480px) {
    .container {
        width: 100%;
        padding: 10px;
    }

    .number {
        width: 30px;
        height: 30px;
        line-height: 30px;
        font-size: 14px;
    }

    button {
        padding: 8px 15px;
        font-size: 14px;
    }

    h1 {
        font-size: 20px;
    }
}