Okay, so I’ve been tasked with looking at branding in SharePoint – again! What do I know about branding? I can change some colours and CSS, but that isn’t the same thing.
Anyway, I’m increasingly taken with Themes over Master Pages. You can do a lot with a theme, and one of it’s main disadvantages as far as I’m concerned (the inability to apply a theme across a hierarchy) can be overcome with extensions (though I’d prefer a Site Admin page option).
Another thing that I recently realised (and then discovered that I’ve probably read about too) is that you can ‘apply’ a theme to all subsites by setting the ‘Alternate CSS URL’ on the Site Settings > Master Page page. You can find the URL to a theme on a site that has that theme applied, and then paste it into the alternate CSS URL field, and apply to all children. Cool! And if you apply a theme to one of these children? Well, the theme will override the Alternate CSS – so your theme will apply.
All of which kind of confuses the heck outta people. You’ve got styles coming from, potentially, the CORE.CSS, alternate CSS, themes, masterpage’s CSS files, the master page itself, and the page. I think it works out as:
…where the lower items win. It’s worth noting that the overriding of styles isn’t that fixed – your master page could pull in the themes, core.css, etc. in a different order if you wanted it to, but this is typically how it seems to be. Just remember that last wins.
New Master Pages are just awkward, though – so many required placeholders, CSS and structural quirks, controls generating things that they shouldn’t. I don’t think I’d go there again unless 1) it’s a WCM site or 2) I really need to change the page structure.