JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <div class="bar">
        <div class="class">
            <br />
            <p>content</p>
            <div class="foo" id="inside">inside</div>
            <p>some other content</p>
            <br />
            <br />
            <br />
            <br />
            <br />
            <br />
            <br />
            <br />
            <br />
            <br />           
        </div>
    </div>
</body>

CSS

.bar {
    max-width: 300px;
    height: 100px;
    overflow-y:scroll;
    overflow-x:hidden;
}
.foo {
    position:absolute;
    background-color: red;
    border-style:solid;
    border-color:black;
}
.class {
    background-color: green;
    border-style:solid;
}