---
title: Themes
summary: What makes up a Silverstripe CMS Theme. How to install one or write your own theme. 
icon: paint-brush
---

# Themes

Themes can be used to kick start your Silverstripe CMS projects, can be stored outside of your application code and your
application can provide multiple unique themes (i.e a mobile theme).

## Downloading

Head to the [ themes section of the addons site ](http://addons.silverstripe.org/add-ons?search=&type=theme) to check out the range of themes the 
community has built. Each theme has a page with links you can use to preview and download it. Themes are published and downloaded using Composer,
just like any other [SilverStripe module](/developer_guides/extending/modules).

## Installation

Themes can be installed through `composer`.

```bash
composer require my_vendor/my_theme [version]
```

*Note:* `[version]` should be replaced with a version constraint if you know it, otherwise leave it blank to pull the latest version compatible with your project.

[alert]
As you've added new files to your Silverstripe CMS installation, make sure you clear the Silverstripe CMS cache by appending
`?flush=1` to your website URL (e.g http://yoursite.com/?flush=1).
[/alert]

### Configuring themes

After installing the files through either method, update the current theme in Silverstripe CMS. This can be done by 
altering the `SSViewer.themes` setting in a [config.yml](../configuration)

**app/_config/app.yml**

```yaml
SilverStripe\View\SSViewer:
  themes:
    - theme_name
    - '$default'
```

There are a variety of ways in which you can specify a theme. The below describe the three
main styles of syntax:

1. You can use the following to point to a theme or path within your root project:

  - `themename` -> A simple name with no slash represents a theme in the `/themes` directory
  - `/some/path/to/theme` - Any `/` prefixed string will be treated as a direct filesystem path to a theme root.
  - `$themeset` - Any `$` prefixed name will refer to a set of themes. By default only `$default` set is configured,
  which represents all module roots with a `templates` directory.

2. Using the `:` syntax you can also specify themes relative to the given module:

  - `myvendor/mymodule:sometheme` - This will specify a standard theme within the given module.
  This will lookup the theme in the `themes` subfolder within this module. E.g.
  `/vendor/myvendor/mymodule/themes/sometheme`.
  Note: This syntax also works without the vendor prefix (`mymodule:sometheme`)
  - `myvendor/mymodule:/some/path` - Rather than looking in the themes subdir, look in the
  exact path within the root of the given module.

3. You can also specify a module root folder directly. 

  - `myvendor/mymodule` - Points to the base folder of the given module.
  - `mymodule:` - Also points to the base folder of the given module, but without a vendor.
  The `:` is necessary to distinguish this from a non-module theme.

## Developing your own theme

A `theme` within Silverstripe CMS is simply a collection of templates and other front end assets such as javascript and CSS located within the `themes` directory. 

![themes:basicfiles.gif](../../_images/basicfiles.gif)

Silverstripe CMS 4 has support for cascading themes, which will allow users to define multiple themes for a project. This means you can have a template defined in any theme, and have it continue to look back through the list of themes until a match is found.

To define extra themes simply add extra entries to the `SilverStripe\View\SSViewer.themes` configuration array. You will probably always want to ensure that you include `'$default'` in your list of themes to ensure that the base templates are used when required.

## Submitting your theme to addons

If you want to submit your theme to the Silverstripe CMS addons directory then check:

* You should ensure your templates are well structured, modular and commented so it's easy for other people to customise 
* Templates should not contain text inside images and all images provided must be open source and not break any 
copyright or license laws. This includes any icons your template uses.
* A theme does not include any PHP files. Only CSS, HTML, images and javascript.
* That your theme contains a `composer.json` file specifying the theme name, author and license, and that it has `"type": "silverstripe-theme"`.

Once you've created your module and set up your Composer configuration, create a new repository and push your theme to a Git host such as [GitHub.com](https://github.com). 

The final step is to [submit your theme to Packagist](https://packagist.org/about#how-to-submit-packages) (the central Composer package repository). Once your theme is listed in Packagist, and has `"type": "silverstripe-theme"` in its configuration, it will automatically be pulled into our addons listing site.

## Links

 * [Themes Listing on silverstripe.org](http://addons.silverstripe.org/add-ons?search=&type=theme)
 * [Themes repositories on github.com](http://github.com/silverstripe-themes)

## Related Lessons
* [Creating your first project](https://www.silverstripe.org/learn/lessons/v4/creating-your-first-project)
* [Migrating static templates into your theme](https://www.silverstripe.org/learn/lessons/v4/migrating-static-templates-into-your-theme-1)