style.css

*{
    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 0.3 s;

}
.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: #9aebc9;

}
.incorrect{
    background: #ff9393;
}