In order to change the text color or style of the map bubble follow these instructions:

The text style in the map bubble can be customized by modifying the HTML block containing the map code.

<div id="iconDesc[@field:ID]" style="display:none">
 <span style="color:red">[@field:Description]</span>
</div>


Use standard CSS (Cascading Style Sheet) to format all or parts of your bubble text.