*{
    margin: 0;
    padding: 0;
}

body,html{
    height: 100%;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: black;
}
.box{
    border-radius: 50%;
    padding: 30px;
    border: 3px solid red;
    transition-duration:.5s;
    background-color: yellow;
}

.btn-div{
    z-index: 2;
    position: absolute;
    top: 70vh;
}

#switch{
    color: green;
    padding: 20px;
    margin: 20px;
}

#effect{
    padding: 20px;
    margin: 20px;
}