JSFiddle - React, Tailwind, and code Playground

HTML

<div id="header">
    <h1>Welcome</h1>
    Header Section
    
</div>
<div id="wrapper">
    <b>Table of data</b>
    <table>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
        <tr><td>data</td></tr>
    </table>
</div>

CSS

#header
{
    position:fixed;
    height:45px;
    top:0px;
    background:grey;
    width:100%;
    text-align:center;
}
#wrapper
{
    margin-top:45px;
}