What is a WordPress theme?
A theme modifies the way the website looks and functions without touching the underlying WordPress core files, which are the specific set of files which make up the WordPress software itself, without any added themes, plugins, or content.
Most of us — we who are not advanced coders — should never edit the core files in any way whatsoever, with the single exception of the wp-config.php file which is edited during the installation process.
Why do we use themes?
The thinking behind the WordPress theme system is smart. It allows people who build websites to make use of an amazingly complex code base — the WordPress core files — with access to all of its power and flexibility, with no danger of breaking that code.
You might say that WordPress itself is like a naked Barbie doll; themes are like outfits she can wear. But they can be pretty fancy outfits which include accessories that allow her to do all kinds of things she couldn’t do otherwise.
But that analogy doesn’t entirely work, because without at least a very basic theme, there can’t be a website at all. The WordPress core files include a default theme — sometimes more than one — so that there is always a theme applied.
The default themes which come with the WordPress core files can be a good choice, since they’re designed and approved by the WordPress core developers and free. The three most recent default themes are named Twenty Fifteen, Twenty Fourteen, Twenty Thirteen and Twenty Twelve.
Where to get themes
The WordPress Theme Directory is the official repository for free themes which have been tested and checked. There are currently over 2,000 themes available for download there.
There are also thousands of themes available for purchase. These are sometimes referred to as “Premium Themes”, but this is just a marketing term. There is no standard for paid themes, and the quality varies a lot. A badly-coded theme can be frustrating to use or even contain dangerous code, so the buyer should always be careful when choosing one. The reputation of the company or developer is the most useful criteria to consider. A close second is the quality of support offered.
Themes are easily uploaded, installed, and activated via the WordPress Admin. This process is covered in another lesson.
Parent themes, child themes, theme frameworks and starter themes
parent theme: Almost all WordPress themes can be and should be used as parent themes. Unless a theme is specifically identified as a child theme, or as a theme framework, starter theme or base theme, it should be considered as and used as an ordinary parent theme. This applies to the vast majority of WordPress themes.
These include all of the functionality and design elements needed to present a WordPress website. You won’t hear most themes specifically referred to as parent themes simply because this is an underlying assumption.
child theme: Any ordinary theme can function as a parent theme by setting it up with a child theme. A child theme inherits all of the design and functionality of its parent theme, and can then be customized. When first set up and activated, a website with a child theme looks and works exactly the same as the website would look and work if its parent theme was activated. It is then customized, leaving the parent theme untouched.
This is done for a very important reason: so that updates can be applied to the parent theme. Remember, updates are crucial in all areas of WordPress. If you modify a theme and subsequently apply an update to it, your modifications will be lost. With this system, the parent theme can be updated without undoing the customizations that were made to the child theme.
A child theme should almost always be used on a WordPress website. And as confusing as this all may sound at first, child themes are actually very simple to set up and work with. We’ll explain how in a subsequent lesson.
The risks of not using a child theme are huge; we advise you to take this very seriously.
theme framework: This is a term with a somewhat fluid and confusing range of meanings. Most commonly, the term refers to a special type of super-charged theme whose purpose is to make the development of feature-rich websites faster and easier for people who produce multiple sites. Genesis, Thesis, and Builder are examples of well-known theme frameworks.
For those who aren’t professionals and aren’t producing multiple websites, theme frameworks are seldom a good choice. Although their advertising will emphasize ease of use, it is for web professionals that the advantages apply. This is because the user needs to learn to use the particular framework itself and its ways, a whole added learning curve. This is useful if you’re planning to use the framework over and over, but mostly an added burden if you’re not.
starter themes, base themes, blank themes: These terms usually refer to stripped-down themes containing very little design or functionality, and are tools for people who develop and distribute full-fledged themes for others to use. Unless and until you’re trying to learn to develop your own themes, you won’t need these.