JSFiddle - React, Tailwind, and code Playground

HTML

<table >
    <tr class="actList">
        <th> a </th> <th> a </th> 
    </tr>
    <tr>
        <td> a </td> <td> a </td> 
    </tr>
</table>

CSS

.actList {
    background-color: rgb(235, 239, 249);
    width: 100%;
}

.activity-header th, .actList th{ text-align: left; font-weight: normal; padding: 0.4em 1em 0.4em 0.3em; }