I am trying to work out what colour the main blue header is where the default vBulletin logo is.
I have looked in the main CSS but I can not for the life of me see the corresponding colour and it's hex value.
Documentation on what stylevars affect what sections is in the making, but probably wont be released for a while yet.
Start here and download the StyleVar Dictionary and the Skinning guide vB4: Skinning Your Forum in 10 Easy Steps (http://www.vbulletin.com/forum/entry.php?2373-vB4-Skinning-Your-Forum-in-10-Easy-Steps). The full final version won't be done until at least Gold.
According to the style variables the colour for the header is #42576a
However when I have create a new logo an uploaded it using that hex value as the background colour it appears to be a different colour.
Hope that makes sense !!
#435164 seem to be the value that you are using. and not #42576a
it's also a gradient.
What is the best way to edit it so the background gradient and colour is "as is" and just replace the text?
You should make a logo with transparent background and this issue will go away.