.p_um {
    display: flex;
    justify-content: center;
}

.sidebar {
    border: black solid 1px;
    height: 98vh;
    width: 12%;
    float: left;
    background-color: white;
    overflow-y: scroll;
    scrollbar-width: thin;
}

.iframe {
    float: right;
    height: 98vh;
    width: 87%;
    border: black solid 1px;
}