How to sticky sidebar in Astra theme?

<!-- Would you please add this CSS under the Additional CSS tab? fahimm.com -->
.sidebar-main {
    drop-shadow(6 5px 3px rgba(9, 30, 66, .1)): ;
    background: #fff;
    box-shadow: 0 2px 10px #dadef1;
    border-radius: 15px;
    overflow: hidden;
    transition: .4s;
    box-sizing: border-box;
    position: sticky;
}

.sidebar-main:hover {
    drop-shadow(6 5px 30px rgba(9, 30, 66, .24));
    background: #fff;
    box-shadow: 0 13px 10px #dadef1;
    border-radius: 15px;
    border: 1px dotted gray;
    overflow: hidden;
    transition: .4s;
    box-sizing: border-box;
}