This is a guide to styling Confluence via CSS (made under Confluence 4.x); in a way that will survive most upgrades; hence It does not use (m)any plugins.

The guide focus'es on doing the styling via the GUI, as opposed to messing around at filesystem level or with tight integrated plugins.

The Scopes page shows the Scope for placing CSS around in Confluence.

Before starting - think about a few Questions:

Q: To Dashboard or Not?

The Dashboard is a "weird" Confluence entity, as it it hard to Maintain and Change, and has no versioning. Read To Dashboard or Not for further info.

Q: Placing Resources?

Resources for the site building can be placed in several locations. Read Placing Resources for further info.

Q: Using Pluings and 3rd Party modules?

This is a gray area, the more use of plugins, the harder to reverse, upgrade and often - the more expensive.

Q: CSS or jquery

A lot of stuff can be acompliced with either CSS or jquery, see the CSS Styling Samples for Confluence 4.X and jquery Styling samples for examples

Q: Confluence 5 ?

Everything can be changed (smile) 
See Preparing for Confluence 5

Subjects:

Atlassian Links:

https://confluence.atlassian.com/display/DOC/Styling+Confluence+with+CSS