JSFiddle - React, Tailwind, and code Playground

HTML

<div class="modal hidden" data-modal-detail="5">
   <div class="container">
        <div class="body">
            <div id="inner-5" class="career-detail-inner-wrap">
            Inner
                <div class="stickyFooter">
                Sticky
                </div>
            </div>
        </div>
    </div>
</div>

CSS

.stickyFooter {       
    width: 90%;
    text-align: center;
    position: fixed;
    bottom: 0;
    height: 150px;
    background-color: red;
}
.body {
    text-align: left;
    -webkit-box-shadow: -7px 0 31px 3px rgba(0, 0, 0, 0.16);
    display: inline-block;
    background-color: white;
    border-radius: 10px;
    margin-top: 150px;
    width: 90%;
}
.container {
        text-align: center;
        vertical-align: middle;
        overflow-y: scroll;
        height: 100%;
        display: block;
        width: 100%;
        position: absolute;
        right: 0;
        left: 0;
        margin: 0 !important;
        max-width: 100%;
        padding: 0;
}
.career-detail-inner-wrap {
  background:green;
  height:800px
 
}