Base code:

(element) {border:1px solid!important;border-radius:10px!important;}

Things to do:

-Replace "(element)" with the name of the element with the borders that you'd like to change... For example:

div.menu_section - The main menus and stuff, with your group description, backgrounds of stuff, etc.

div.zebra - Shouts/Comments

h1 - Headers

-Replace the "1px" part in "border:1px" to how thick you'd like your borders to be. 4px or 5px is recommended!

-Replace "" with the color you'd like the borders to be.

-Replace the "10px" in "border-radius:10px" with how rounded you'd like the corners to be. 10px is recommended!

I hope this helps!

- @Amjam