.app{
    max-width: 90%;
    background-color: rgb(253, 253, 253);
    width: 600px;
    margin: 100px auto 0;
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 0 5px rgb(6, 13, 0),
    0 0 25px rgb(0, 0, 0)
}
*{
    box-sizing: border-box;
}
body{
    background-color: blue;
}
.btn{
    background-color: #fff;
    color: #222;
    font-weight: 500;
    width: 100%;
    border: 1px solid black;
    padding: 10px;
    margin: 10px 0;
    text-align: left;
    border-radius: 5px;
    cursor: pointer;
    transition: all 0.5s;
} 
.btn:hover{
    background-color: #222;
    color: #fff;
}
#dalsi{
    width: 150px;
    background-color: blue;
    color: #fff;
    font-weight: 500;
    border: 0;
    padding: 10px;
    margin: 20px auto 0;
    border-radius: 5px;
    cursor: pointer;
    display: none;
}
.correct{
    background-color: green;
}
.incorrect{
    background-color: rgb(146, 5, 5);
}
#nextBTN{
    background-color: green;
    min-width: 110px;
    min-height: 40px;
    position: relative;
    left: 400px;
    border-radius: 20px;

}
#nextBTN:hover {
    box-shadow: 0 0 5px rgb(6, 13, 0),
    0 0 25px rgb(0, 0, 0)
}
h1{
    font-family: "open sans";
}