body{
    background-image: url("world.png");
    background-size: cover;
    max-height: 100vh;
}

.quiz-box{
    width: 700px;
    margin: 0 auto;
    /*background-color: chartreuse;*/
    height: 700px;
    padding: 1px;
}
.quiz-box h1{
    font-size: 35px;
    text-align: center;
    font-family: "Bookman Old Style", "Comic Sans MS", cursive;
    border-radius: 10px;
    margin: 20px auto;
    width: 70%;
}

.main-container{
    display: flex;
    flex-wrap: wrap;
    width: 560px;
    /*background-color: aliceblue;*/
    justify-content:space-around;
    margin: 0 auto;
    height: 560px;

}

.container{
    width: 170px;
    height: 170px;
}

.card{
    text-align: center;
    border-radius: 10%;
    width: 170px;
    height: 170px;
    font-family: Arial, sans-serif;
    font-size: 20px;
    font-weight: bolder;
    position: relative;
    transition: all 1s linear;
    transform-style: preserve-3d;
}

.front , .back , .mid{
    height: 100%;
    width: 100%;
    color: orange;
    background-color: aquamarine;
    position: absolute;
    border-radius: 10px;
}

.front{
    z-index:1;
    backface-visibility: hidden;
}

.back{
    z-index:-1;
    transform: rotateY(180deg);
}

.card:hover{
    transform: rotateY(180deg);
}