I started working on another Joomla/SMF integrated web site for a friend of mine, and I came across this nifty little page called the CSS Integrator
. This thing saved me a lot
of time getting the SMF and Joomla templates to play nicely together.
It's pretty simple. First, you send the script your SMF theme's CSS file. It processes it and sends back a modified version of it. All it's really doing is making a "child class" of your CSS entries with the name you specify.
After that's done, you need to change your template's index.template.php file a tad.
First, where it's calling the template's CSS file, you need to change that to the name of the new CSS file.
Then, you have to add two bits to the file.
After the <body> tag, add:
(Adjust the name of the class for whatever you specified when you ran the integrator script.)
Then, right before the </body> tag, add:
And that's it. The SMF template will now render perfectly inside of your CMS without messing up the CMS's theme in any way.
Granted, technically you're not done. For XHTML validation you'll need to rip out the headers out of the SMF template, and move the CSS call into the CMS's theme and so on. (Not required but recommended) But that part's the easy part, and there's good documentation here in the forums for that if needed.
Hope this helps someone. Edit:
Couldn't something like this be done as an SMF Package or Joomla component? A little admin panel addon that lets you patch and unpatch the selected theme's CSS and index.template.php file? Would be a huge benefit to anyone wanting to do Joomla/SMF integration I would think.