How do you customise a bundled theme?

[Michael S]

Is it possible to modify the bundled themes stylesheets and/or layout? What's involved? What are the risks/considerations?

[Jeremy Largman · Accepted solution]

The documentation @Brendan Patterson mentions is good for customising the default theme, but if you want to customise one of the other themes, you'll have to modify that theme's JAR file.

Actually it's this somewhat buried comment that you need, to modify a bundled plugin. From Plugin loading strategies in Confluence:

Bundled plugins are included in a zip of jars called atlassian-bundled-plugins.zip which is on the main Confluence classpath, in a resources directory - <tt><confluence-install>/confluence/WEB-INF/classes/com/atlassian/confluence/setup</tt>. At Confluence startup, they are extracted and copied into the $CONFLUENCE_HOME/bundled-plugins directory, from whence they are loaded. To remove a bundled plugin (you shouldn't normally have to do this), remove the plugin from the atlassian-bundled-plugins.zip file and the bundled-plugins directory, otherwise Confluence will just put it back in place on the next startup.

So, if you want to modify something in a bundled theme that's not the default theme, you can extract the correct bundled theme from atlassian-bundled-plugins.zip, rezip the folder, then restart Confluence.

[David Peterson]

Alternately, just unzip the jar file, change the plugin key, and leave the original as is. You can have both installed safely, although it obviously could get a bit confusing with two similar themes installed.

[Brendan Patterson]

The Confluence docs cover this pretty well:
Modifying Look and Feel (for themes)

Excerpt:

Here's how you can define a new look and feel for Confluence in your theme:

1. Layout : Edit Confluence's layout by modifying the decorator files that are used to define it.
   
   • Working with Decorators
   • Velocity Template Overview
   • Configuring the atlassian.plugin.xml file to reference the decorators
2. Colour schemes : Configure a new colour scheme for your theme. Optional
   
   • Configuring a new colour scheme
   • Configuring the atlassian.plugin.xml file to include the new colour scheme
3. Stylesheet : Include a stylesheet to define your theme. Optional