JSFiddle - React, Tailwind, and code Playground

HTML

<div id="test">этот текст должен быть всё время сверху</div>
<table id="table">
    <tr>
        <td>

        </td>
    </tr>
    <tr>
        <td>

                <table>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr>
                <tr><td>aaa</td> <td>bbb</td> <td>ccc</td></tr> 
                </table> 

        </td>
    </tr>
</table>

CSS

#test {
    position:fixed;
    top:0;
    left:0;
    background:#fff;
}
#table {
    margin-top: 20px;
}
td{
    border:1px solid #000;
}