JSFiddle - React, Tailwind, and code Playground

HTML

<div class="data-holder">
    <div id="whitish"></div>
    <div id="shadow"></div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
    <div class="block">hello</div>
</div>

CSS

.data-holder {
    width: 200px;
    height: 300px;
    border: 1px solid #ddd;
    overflow: auto;
    position: relative;
}

#shadow {
    position: absolute;
    left: 0;
    height: 30px;
    width: 180px;
    z-index: 9999;
    display: none;
    background:	radial-gradient(farthest-side at 50% 0, rgba(0,0,0,.2), rgba(0,0,0,0)) 0 100%;
}

#shadow + div {
    padding-top: 10px;
}

#whitish {
    background: #fff;
    position: absolute;
    top: 0;
    width: 100%;
    height: 10px;
    z-index: 999999;
}

.block {
    background: #f00;
}

JavaScript

$(document).ready(function(){
    $('.data-holder').scroll(function(){
        $("#shadow, #whitish").css({'top': $('.data-holder').scrollTop() + 'px'});
        var y = $('.data-holder').scrollTop();
        if( y > 0 ){
            $("#shadow").show();
        } else {
            $("#shadow").hide();
        }
    });
})