kingjeffrey

From the authors of <a href="https://wordpress.org/extend/plugins/wp-typography/" rel="ugc">wp-Typography</a> comes wp-AuthorComment, allowing you to uniquely style post author’s comments.
View the <a href="http://kingdesk.com/projects/wp-authorcomment/" title="wp-AuthorComment Homepage" rel="nofollow ugc">wp-AuthorComment homepage</a> for more information.

wp-AuthorComment

Uniquely style the post author's comments.

Maxaud

This plugin allows you to define different CSS rules that get loaded into the page’s for specific devices.
Includes checks for 18 different tablet options and 13 different phone options.
This can be useful if you need to target specific phones or tablets to make CSS changes or show certain advertisements for certain devices.
For more options or if you feel like donating, check out the <a href="http://codecanyon.net/item/mobile-css-pro/3182318/" title="Mobile CSS Pro" rel="nofollow ugc">PRO version of Mobile CSS</a> that is available for purchase.

Mobile CSS

Allows you to define different CSS styles that get loaded for specific mobile devices.

wp-AuthorComment vs Mobile CSS