2. A child theme is a theme that inherits the functionality and
styling of another theme, called the parent theme. Child themes are
the recommended way of modifying an existing theme. - WordPress
Codex
3. Your Parent Theme is like your head. Your Child Theme is
like a hat. Customizing the Child Theme is like changing the hat.
Updating the Parent Theme is like getting a haircut.
4. If you modify a theme directly and it is updated, then your
modifications may be lost. By using a child theme you will ensure
that your modifications are preserved. - WordPress Codex
5. When you edit the CSS file(s) in your theme, you are
changing the theme files. When you update a theme, it overwrites
those files. Your changes will disappear with it.
6. Technically: No. If you arent using a child theme, but you
are using a plugin to manage custom CSS, such as JetPack, then this
isnt the case. But remember, if youre using JetPacks Custom CSS
module and you change your themes, your custom CSS will
disappear.
7. I will be using the current WordPress default theme: Twenty
Fifteen I will be editing the files live on the site. (Dont do this
in real life. Ill explain soon.) I needed a third bullet
point.
8. Twenty Fifteen with no modifications.
9. Only Twenty Fifteen is installed.
10. functions.php style.css Yup thats it!
11. functions.php
12. How does it know which is the parent theme?
13. style.css
14. Put both of those files, functions.php and style.css into a
folder together and name it whatever you are naming your child
theme. Put that folder into a zip file.
15. Zip file with the folder inside.
16. Files inside the folder within the zip file.
17. Add Themes page with Upload Theme in the top left.
18. Find your new child theme file on your computer, then
select it and press Install Now.
19. What it will say if the Parent Theme is already
installed.
20. Parent Theme is not installed, but can be installed from
the WordPress.org Theme Directory.
21. Parent Theme is not installed and cant be automatically
installed from the WordPress.org Theme Directory.
22. Child Theme is active!
23. Note: Whenever possible, you should not make changes to
your websites files directly on the server, unless youre 100% sure
that it wont cause problems. Whenever possible, make a copy of the
file you want to edit, make the changes on your computer and then
use FTP to upload the new file.
24. Lets change the font of the Entry Title. We can see in the
Inspector that its class is entry-title.
25. I have added the change to my Child Themes style.css file.
Note that there isnt any other text in this file. All of the Parent
Themes styles are still in the Parent Themes files. But my changes
to the Child Themes style.css file will override the styles in the
Parent Themes style.css.
26. Note the theme you are currently editing.
27. Dont forget to click update.
28. Oh, look! A different font!
29. How about changing the sidebar background
30. The sidebars background being changed in the style.css
file.
31. Blue is always fun.
32. Make a quick change to the font colors in the sidebar.
33. That looks pretty good.
34. Making a functionality change. Keep track of which files
youre editing so that you dont accidentally edit the wrong
file.
35. Changes to style.css override any preexisting styles for
that element or class that exists in the Parent Themes style.css
Changes to functions.php will be loaded in addition to the Parent
Themes functions.php This means that if you need to remove an
action, you will need to declare that in the Childs
functions.php
36. You can now update Twenty Fifteen anytime an update is
available without having to worry about losing any of your changes.
You can also install this Child Theme on any other WordPress site
and it will look exactly the same there, no extra configuration
required. You can even upload it to WordPress.org
37. Typically, a Starter Theme is one that you are expected to
edit directly and turn into its own parent theme. It is often
incomplete. Underscores, also called _s, is a very popular example
of a starter theme.
38. Typically, a Framework is a parent theme which often has
little or no styling, which you are supposed to create a Child
Theme for to add styles and functionality. Genesis is a very
popular example of a framework.
