Themes allow you to customize and personalize the look and feel of the user's web client. To change the theme go to Action > Change Theme.
Once the Change Theme dialog appears, select a theme from the Theme drop down menu list. The selected theme will display a sample in the dialog. Click Apply to save the theme to your web client.
Warning: Applying a new theme requires all tabs to be closed to apply new settings. Be sure drafts are all saved.