position

left:rem;
pushing from left ->

.box-2{
    background-color: tomato;
    /* ⚜️> */
    position: relative;
    left:5rem;
    bottom: 4rem;
    /* <⚜️ */
}

z-index: -1;

.box-2{
    background-color: tomato;
    /* ⚜️> */
    position: relative;
    left:4rem;
    bottom: 4rem;
    z-index: -1;
    /* <⚜️ */
}

z-index: 1;