2 tips on css
CSS debugging
I'm sure this technique is used by many web developers, but it took me some time to figure out for myself.
When working on a specific style class it's often helpful to add a red border around it by adding the following line:
border: solid 1px red
This makes all the items which use this class very easy to notice and really helps solving the problems with the style sheets.
Centering a block without using HTML <center> tag
To align a block to the center of the containing block you can set both 'margin-left' and 'margin-right' properties of the block to 'auto'.
The width of the internal block should of course be smaller than the parent's.