Yes, and it's very simple as well.
When you create a card, you can use the specific color and text font of your site, and the reaction will look natural and in place on your site.
You can enter the color code and font manually, or use the picker to automatically identify colors and fonts which are used on the site:
Once a card is created, it can be used again for more reactions, and the color and font choices will remain consistent. You can also "Copy & Edit" to duplicate the card and make small changes.