If you need to customize theme files at a code level, you’ll need to do so using a child theme. Any changes made via AppearanceEditor to a parent theme will be lost if you ever run a theme update.
For more on creating and using a child theme, please see: Creating a Child Theme
Child theme ZIP files can be installed from AppearanceThemesAdd NewUpload Theme.
A basic child theme to get started with. No changes have been made yet.
Download SiteOrigin Unwind Child Theme – Starter