Hi,
You are using "LightMart" so you should create your forum topic in this category:
www.flexiblewebdesign.com/forum-joomla-virtuemart-template-lightmart-support
but that's fine for now.
to change the border color:
open this PHP file:
/templates/flexilbe_lightmart/html/com_virtuemart/category/default.php
and look for this property:
and change the HEX color code (#ff0000) as you wish.
TIP: you will find that property in 6 different places (within the same PHP file), so you need to make the change for all of them. You should better use CTRL+F to find them all.
Regards,
Support