VS 2008 supports a new tool window inside the IDE called
"Manage Styles". This shows all of the CSS stylesheets, and
their corresponding rules, for the page you are currently editing. It can
be used both when you are in design-view, as well as when you are in source
view on a page:
Figure 2
A circle around a CSS rule in the manage
styles window indicates that particular rule is in use within the current
document. Using the mouse to hover over the rule allows you to quickly
see the CSS rule values:
Figure 3
You can then either right-click on a CSS rule and select
"Modify Style" to bring up a graphical CSS rules editor, or you
can double click on the rule in the manage styles window to automatically open
the stylesheet file and jump immediately to the CSS source definition to
edit (with full intellisense):
Figure 4
For even more tips/tricks about how to best use the
"Manage Styles" tool window please read this blog post.