A author’s comment if has different background color, or different text style or even border, helps readers to easily locate what Author has to say if a question is asked in comments or even what he thinks of the comments coming.
This simple tutorial will help you achieve same and that too without any plugin used.
For WordPress Users:
Note: Do take backup of your theme before you try this.
01. Go to Appearance => Editor.
02. Then choose style.css file from right hand side and add below code: