.main{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
}

.box1{
    height: 400px;
    width:400px;
    background-color: red;
    display: flex;
    justify-content: center;
    align-items: center;
}
.box2{
    height: 400px;
    width:400px;
    background-color: green;
    display: flex;
    justify-content: center;
    align-items: center;
}

.button{
    background-color: blue;
    padding: 20px 35px;
    border-radius: 5px;
    color: white;
    font-weight: bold;
    font-size: 20px;
    display: none;
}

.active{
    display: block;
}