.wp {
            display: flex;
            justify-content: center;
            align-items: center;
        }
        .box {
        }
.wp {
    border: 1px solid red;
    width: 300px;
    height: 300px;
}

.box {
    background: green;    
}

.box.size{
    width: 100px;
    height: 100px;
}