Not all improvments can be done using CSS or code snippets. Some requires changes in files. You may have to dive in code. And there’s an absolute rule: never touch a single line of code in a WorPress theme.
Why? There’s a single reason: WordPress themes are updated from time to time. If you made changes in theme, all will be lost at first release.
That’s why you can’t change, add, remove code or files in a theme you got in WordPress repository, in a Themes Shop or marketplace.
If you need to do it, and you may have to, there’s a solution anyway: you have to…
Create a child theme for Twenty Seventeen
The child theme is a new theme which inherits from its parent. All its parent have, he have too. And you can extend it, cause this child, your child theme, will not be update, never. Its parent will. Not him.
If you want to know more about child themes, read WordPress training course.
You can create your child theme from scratch, using a text or code editor. But it is long and painful.
And there’s an awesome plugin that can help us a lot: Child Theme Configurator.
Install it, activate it. Now your child theme is just a few clicks away.
In WordPress back-office, go to Tools > Child Themes. Follow given instructions as shown on screenshot:
Click on Analyse. You should see something like this:
If you already add CSS rules or configured the parent theme, go directly to the 8th step: Copy Menus, Widgets and other Customizer Settings from the Parent Theme to the Child Theme and check the box.
If you’re working on a fresh and clean install, you don’t need to check it.
Next, go to the bottom of your screen and click on Create New Child Theme button.
Your child theme is now online, go to Appearance and activate it.
As long as you work on your child theme, let the plugin active. It will help you when you’ll need to copy files from parent theme for example.
And when you’re done, you can safely deactivate it.
Child Theme Configurator alternatives
I’ve tried a lot of child themes plugin from the WordPress repository. There is not one that performs as well as Child Theme Configurator. You can try one at your own risk, but remember that this one is by far the most effective.