Basically this whole site is the Dolphin default template that I just edited. I didn't edit a lot of files but I did make a lot of edits in each file.
Most of it has been done by editing .css files in various locations. There are a lot of them, it's a matter of finding the right one.
Dolphin:
/templates/tmpl_uni/css/general.css
-Most fonts, colors, tables, backgrounds, etc can be changed.
/templates/tmpl_uni/css/profile_view.css
-I edited for slightly more transparent member profile pages when changing background colors or profile picture backgrounds.
/templates/tmpl_uni/css/anchor.css
-I haven't touched this one, but some people do.
Rarely:
templates/base/css/cmts.css
-I edited to make comment member icons larger than the default.
Orca Forums is a little more of a pain.
/orca/layout/base/css/main.css
Edit that file, but after making your changes you do have to login to your Dolphin Admin panel. Go to the orca admin area and compile the language file. Click the little "en" link in the upper right.
You have to do this after each change you make to that file in order to right the changes to the server. This can be time consuming and a tedious task. But this is how it should be done.
I do not use groups currently, but there is a good chance you will have to do the same to groups and compile the language file for them as well. Clicking the little "en" in the group admin area.
/groups/orca/layout/base/css/main.css
-It may be the exactally the same file as the orca main.css file, I haven't checked it.
Basically then just finding the right area in the .css file to edit. Make fonts bigger, change the color, make them underlined, bold, etc.