I have created a table in Google Visualization which uses the following code:
Take a quick peak at https://developers.google.com/chart/interactive/docs/gallery/table for more information, but you should be able to link in your own style sheet in the head tag, then reference the class in JS. The only thing I'm not certain is whether you can create custom CSS files with Wordpress, but this would be the general idea:
HTML:
Javascript:
var cssClassNames = {headerRow: 'myAwesomeClass'};
CSS:
.myAwesomeClass {
font-size: 24px;
}