JSFiddle - React, Tailwind, and code Playground

HTML

<div class="parent">
    <div class="child yellow"></div>
    <div class="child blue"></div>
    <div class="child red"></div>
</div>

CSS

.child {
    border-style: solid;
    border-width: 0 2px 2px 2px;
    background: white;
    height: 100px;
}

.child:first-child {
    border-top-width: 2px;
}

.yellow { 
    border-color: yellow;
}

.blue {
    border-color: blue;
}

.red {
    border-color: red;
}

.parent {
    width: 500px; /* or any other width */
    height: 100vh; /* or any other fixed height */
    overflow-y: auto; /* make scrollable */
    box-shadow: inset 2px 2px 0 black, inset -2px -2px 0 black;
}