JSFiddle - React, Tailwind, and code Playground

HTML

<div class="viewport">
    <div class="itemContainer">
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
        <div class="item"></div>
    </div>
</div>

CSS

.item {
    width: 100px;
    height: 100px;
    background: lightblue;
    float: left;
    margin-right: 20px;
}
.itemContainer {
    width: 1000px;
    float: left;
}

.viewport {
    float: left;
    width: 350px;
    border: thin red solid;
    overflow: scroll;
}