Basically, the principle is same: adding or modifying the existing CSS code in the The reason why one person failed to customize it is, in his theme, the author box design was not defined in CSS style sheet. So, he added the CSS with name .file of your current theme.
The main problem in his case was, there was a separate php file (visible in theme editor) which was named . So, his customization was not applied. So, take care of this thing. Re-naming it as instead of in the stylesheet solved the problem.
So, your first work is to find out where is the code that is defining your author box infile of your current theme. Searching with author (after copy pasting the code in Notepad) should normally find it. If you do not find it, examine your theme for the corresponding name of the php file. You must name accordingly.
To get something like my Author box, you have to add (or modify) the code to like this :
text-shadow:#fff 0 1px 1px;
margin:0 0 30px;
padding:10px 60px 10px 10px;
border:1px solid #EAEDEF;
margin:0 10px 0 0;
Firstly read this post to understand the meaning of the above codes.
.author-box defines how the box will look.
.author-box img defines the look of the Gravatar inside your author box. If you do not want customize Gravatar, just omit the code.
background-image defines the position of our logo (the Lotus), if you do not want to show, omit this line.
Author box plain with 1px border:
Border color has been made black (#000000), 1 px wide. Others has been deleted.
Author box without any border:
Border has been deleted.
Author box without any border and rounded corners:
Border has been made of same color that of background, it has been rounded using CSS. Follow this tutorial to create borders rounded. If we make the border of different color, you will understand it:
About the border of author image
If you do not want any border, simply set it to none. If you want to make one side (usually the lower) thick, mention border as 2px 2px 7px 2px (this is just an example).
Just, we have used
border: 1px dotted #000;