You can create your own text component in which you can extend the RTE plugin.
The plugin can be customized itself (see the second link from Yogesh) but you can also add your own styles in a css file that will target the specified elements. Just create the specified css files in include it in the clientlib for the component. Then make sure that clientlib is also included in your app. Look at the following code from the link Yogesh sent:
You may want to specify stylesheets that are optimized for rich text editing. Due to technical restrictions the CSS context is lost in the editor, so you may want to emulate this context to improve the WYSIWYG experience. The Rich Text Editor uses a container DOM element with an ID of CQrte which may be used to provide different styles for viewing and editing: #CQ td { // defines the style for viewing } #CQrte td { // defines the style for editing }
Hope that will solve your problems!