How about simply (Please note, come up with a better name for the class name this is simply an example):
.centerText{
text-align: center;
}
<div>
<table style="width:100%">
<tbody>
<tr>
<td class="centerText">Cell 1</td>
<td>Cell 2</td>
</tr>
<tr>
<td class="centerText">Cell 3</td>
<td>Cell 4</td>
</tr>
</tbody>
</table>
</div>
Example here
You can place the css in a separate file, which is recommended.
In my example, I created a file called styles.css and placed my css rules in it.
Then include it in the html document in the <head> section as follows:
<head>
<link href="styles.css" rel="stylesheet" type="text/css">
</head>
The alternative, not creating a seperate css file, not recommended at all...
Create <style> block in your <head> in the html document. Then just place your rules there.
<head>
<style type="text/css">
.centerText{
text-align: center;
}
</style>
</head>