Changing the Default Site Theme
The default site theme will be applied to every new space created and to every space using the default, but can be changed at any point.
Vanilla, a built-in theme, is automatically set as the default site theme when Theme Press is installed. Any new space created in the site will use the default site theme when the space is created (as will each page in the space.) Additionally, this default site theme is used for all Confluence admin pages, such as the user profile page. It is also automatically applied to the Theme Press Default space, which houses architect pages.
The Theme Press Default Site Theme can be changed to any theme of your choice. (Keep in mind that by doing so, any space that is configured to use the site theme will be themed by this change.)
Click the magnifying glass to the right of the Site Theme setting.
Select a theme from the Available Themes section.
The Change Site Default Theme window opens.
Confirm the change by checking the box.
Click the OK button and wait for the theme to update.