In addition to using existing themes and style sets, you can make your own. You can create new themes and style sets from scratch or tweak existing ones. By using custom styles and themes, you can easily control exactly how your document looks.
Your theme is saved and will be found in a special Custom group in the Themes menu.
Custom themes you’ve saved will be available for use in all your documents. You can even share the theme file with others so they can also use your new theme.