What we need to do is set up a theme to inherit the benefits we get from our chosen theme, that we can then adjust to suit our needs. This is called a sub-theme. Let's get started, using Bartik as the parent theme.
Back in PhpStorm, in the root directory of your project, navigate to the
themes directory. Right now this directory is empty apart from a README file. We'll first create a directory to place our sub-theme in. It is good practice to place your own themes in a folder named
custom, and any contributed themes in a sub folder named
contrib (more on contributed themes later). Inside the newly created
custom folder, we'll begin creating our sub-theme. We need to follow a few naming rules: it must start ...