*{
    margin: 0;
    padding: 0;
    font-family: 'Poppins', sans-serif;
    box-sizing: border-box;
    }
    body{
        background: #001e4d;
    }
    .app{
        background: #fff;
        width: 90%;
        max-width: 600px;
        margin: 100px auto 0;
        border-radius: 10px;
        padding: 30px;
    }
    .app h1{
        font-size: 25px;
        color: #001e4d;
        font-weight: 600;
        border-bottom: 1px solid #333;
        padding-bottom: 30px;
    }
    .quiz{
        padding: 20px 0;
    }
    .quiz h2{
            font-size: 18px;
            color: #001e4d;
            font-weight: 600;
    }
    .btn{
        background: #fff;
        color: #222;
        font-weight: 500;
        width: 100%;
        border: 1px solid #222;
        padding: 10px;
        margin: 10px 0;
        text-align: left;
        border-radius: 4px;
        cursor: pointer;
        transition: all 0.3s;
    }
    .btn:hover:not([disabled]){
        background: #222;
        color: #fff;
    }
    .btn:disabled{
        cursor: no-drop;
    }
    #next-btn{
        background: #001e4d;
        color: #fff;
        font-weight: 500;
        width: 150px;
        border: 0;
        padding: 10px;
        margin: 20px auto 0;
        border-radius: 4px;
        cursor: pointer;
        display: none; 
    }
    .correct{
        background: #ffffff;
        }
        .incorrect{
        background: #ffffff;
        }