.roundSidedBorder001 {
    position: relative;
    background: white;
    border-radius: 0% 0% 0% 0% / 0% 0% 0% 0%;
    box-shadow: 20px 20px rgba(0,0,0,.15);
    transition: all .4s ease;
    padding : 1rem;
    border : solid 1px #dddddd;
}

    .roundSidedBorder001:hover {
        border-radius: 0% 0% 50% 50% / 0% 0% 5% 5%;
        box-shadow: 10px 10px rgba(0,0,0,.25);
    }