JSFiddle - React, Tailwind, and code Playground

HTML

<div class="header">Title</div>
<div class="menu">
    <ul>
        <li>option 1</li>
        <li>second option</li>
    </ul>
</div>
<div class="content">
    <h1>ASDUAHSD ASDASD ASID AS DAKSH</h1>
    <h1>ASDUAHSD ASDASD ASID AS DAKSH</h1>
    <h1>ASDUAHSD ASDASD ASID AS DAKSH</h1>
    <h1>ASDUAHSD ASDASD ASID AS DAKSH</h1>
    <h1>ASDUAHSD ASDASD ASID AS DAKSH</h1>
    <h1>ASDUAHSD ASDASD ASID AS DAKSH</h1>
    <h1>ASDUAHSD ASDASD ASID AS DAKSH</h1>
</div>

CSS

.header {
    background-color: yellow;
    padding: 10px;
}

.menu {
    background-color: blue;
    float: left;
    width: 20%;
}

.content {
    background-color: red;
    float: left;
    width: 80%;
}