SharePoint 2010 core.css multiple versions?

Question

Hi I'm new to SP 2010, picking up a site someone else customized.

I opened the site's master page then followed the link to the css section to change.

Saved the change and the page looked fine. But, I went back to make another change and the original change was overwritten!

This is only 1 site, 1 master page, but i noticed something weird - there are multiple core.css files in the top-level site, all in weird randomly named folders in {top-level site}/_catalogs/theme/themed/1386CE2C/corev4-80A8FAC2.css

I'm only familiar with SP 2007 customization, so I'm not quite sure what's going on here.

Can someone try to explain or point me to a link that will help? thanks!

Answer 1

This was a good read:

Themable CSS Registration and Rendering for SharePoint 2010

Answer 2

In SharePoint 2010, the Core.CSS file is automatically generated with Themes.

The CSS base files are populated with lots of attributes that are parsed when a theme is set, thus creating a new Core.CSS file which has the elements for a specific theme dropped in.

What you're better doing, is creating a new CSS file from scratch, and filling in your customisatiosn there, then add it to the masterpage.

As a general rule, never modify anything SharePoint gives to you in the 12 hive (SharePoint Root in 2010). Changes will more often than not just be overwritten, especialyl with a service pack installation.

Answer 3

ahum the 14 hive ;-)