[[understanding-themes]]

=== Concept: Themes

[role="summary"]
Overview of themes and where to obtain them.

(((Theme,overview)))
(((Theme,core)))
(((Core theme,overview)))
(((Theme,third-party)))
(((Third-party theme,overview)))
(((Theme,custom)))
(((Custom theme,overview)))

==== Prerequisite knowledge

<<understanding-drupal>>

==== What is a Theme?

A theme is a set of files that define the visual look and feel of your site.
The core software and modules that run on your site determine which
_content_ (including HTML text and other data stored in the database, uploaded
images, and any other asset files) is displayed on the pages of your site. The
theme determines the HTML markup and CSS styling that wraps the content.

The core software provides several basic themes with the core distribution.
These themes have largely been designed and built by the community over the last
several years and will all be good choices for building your first sites and
becoming more familiar with how the core software works.

Drupal is a well-established CMS so the market for 3rd party themes - both free
and paid - is very robust.

If none of the 3rd party options suit your needs, you'll need to create a custom
theme. A custom theme can be as simple as a single CSS file that adds styling to
the markup provided by the core software.  Guidance for creating custom themes
in Drupal 8 can be found in the
https://www.drupal.org/docs/8/theming[_Drupal.org_ community documentation page
"Theming Drupal"].

==== Related topics

* <<extend-theme-find>>
* <<extend-theme-install>>
* <<understanding-modules>>

==== Additional resources

https://www.drupal.org/docs/8/theming[_Drupal.org_ community documenation page "Theming Drupal"]


*Attributions*

Written and edited by https://www.drupal.org/u/jgrubb[John Grubb] and
https://www.drupal.org/u/jhodgdon[Jennifer Hodgdon].
