Share Perran says,
"When you apply a theme to a site in V3 (just like V2), the theme.css is not the file which is actually applied to the site.
"Instead your theme and the other CSS is combined forming a file called something to the effect of “ThemeName1011-65001.CSS”. This is the file you need to edit.
"Select View Source from the browser while viewing your site, you'll notice that file is applied.
"You will find this file in the _themes folder using SharePoint Designer 2007."
But what if you don't have or want to use SharePoint Designer for this? How does one get at the combined file?
I prefer to apply a new theme and make future changes to the file system. Tigirry provides a great HOW-TO in his blog.
Subsequent changes to the custom theme seem surprisingly tough though. Most posts indicate that to get further changes to take, one must apply a different theme with Site Settings (Home > Site Settings > Site Theme) and then re-apply the desired theme. (Bil Simser calls it the "Rinse, Lather, Repeat" method. LOL!)
Even then, I found the changes weren't being made probably due to an ISAPI cache or something. I found I had to
use an extra step to make my changes
- edit and save the css file
- recycle the app pool
- apply another theme
- re-apply the desired theme
Here are two approaches to avoid this problem provided by Bil Simser:
I still like to edit files directly so I'll try creating a web part, but how to code the pool recycle? Mmmm.