JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdn.ckeditor.com/4.5.4/standard/ckeditor.js"></script>
<div contentEditable=true>
    
    <table border="0" cellpadding="0" cellspacing="0" class="MyTable">
	<caption>Shopping with border=0</caption>
	<tbody>
		<tr>
			<th scope="row">price 1</th>
			<td>9,20 &euro;</td>
		</tr>
		<tr>
			<th scope="row">price 2</th>
			<td>70,56 &euro;</td>
		</tr>
	</tbody>
</table>
    <p></p>
        <table border="1" cellpadding="0" cellspacing="0" class="MyTable">
	<caption>Shopping with border=1</caption>
	<tbody>
		<tr>
			<th scope="row">price 1</th>
			<td>9,20 &euro;</td>
		</tr>
		<tr>
			<th scope="row">price 2</th>
			<td>70,56 &euro;</td>
		</tr>
	</tbody>
</table>
</div>

CSS

.MyTable {
    border-collapse:collapse;
    border:1px solid blue;
    background-color: #00DD00;
}

.MyTable td, .MyTable th{
    border:1px solid blue;
        padding: 5px 1em;
}

JavaScript

CKEDITOR.config.allowedContent = true;

CKEDITOR.stylesSet.add( 'my_styles', [
    // Block-level styles
    { name: 'Nice table', element: 'table', attributes: { 'class': 'MyTable' } }
] );

CKEDITOR.config.stylesSet = 'my_styles';