---
layout: docs
title: Themes
permalink: /docs/themes/
---

Jekyll has an extensive theme system, which allows you to leverage community-maintained templates and styles to customize your site's presentation. Jekyll themes package layouts, includes, and stylesheets in a way that can be overridden by your site's content.

## Installing a theme

1. To install a theme, first, add the theme to your site's `Gemfile`:

        gem 'my-awesome-jekyll-theme'

2. Save the changes to your `Gemfile`
3. Run the command `bundle install` to install the theme
4. Finally, activate the theme by adding the following to your site's `_config.yml`:

        theme: my-awesome-jekyll-theme

You can have multiple themes listed in your site's Gemfile, but only one theme can be selected in your site's `_config.yml`.
{: .note .info }

## Overriding theme defaults

Jekyll themes set default layouts, includes, and stylesheets, that can be overridden by your site's content. For example, if your selected theme has a `page` layout, you can override the theme's layout by creating your own `page` layout in the `_layouts` folder (e.g., `_layouts/page.html`).

Jekyll will look first to your site's content, before looking to the theme's defaults, for any requested file in the following folders:

* `/_layouts`
* `/_includes`
* `/_sass`

Refer to your selected theme's documentation and source repository for more information on what files you can override.
{: .note .info}

## Creating a theme

Jekyll themes are distributed as Ruby gems. The only required file is the [Ruby Gemspec](http://guides.rubygems.org/specification-reference/). Here's an example of a minimal Gemspec for the `my-awesome-jekyll-theme` theme, saved as `/my-awsome-jekyll-theme.gemspec`:

{% highlight ruby %}
Gem::Specification.new do |s|
  s.name     = '<THEME TITLE>'
  s.version  = '0.1.0'
  s.license  = 'MIT'
  s.summary  = '<THEME DESCRIPTION>'
  s.author   = '<YOUR NAME>'
  s.email    = '<YOUR EMAIL>'
  s.homepage = 'https://github.com/jekyll/my-awesome-jekyll-theme'
  s.files    = `git ls-files -z`.split("\x0").grep(%r{^_(sass|includes|layouts)/})
end
{% endhighlight %}

### Layouts and includes

Theme layouts and includes work just like they work in any Jekyll site. Place layouts in your theme's `/_layouts` folder, and place includes in your themes `/_includes` folder.

For example, if your theme has a `/_layouts/page.html` file, and a page has `layout: page` in its YAML front matter, Jekyll will first look to the site's `_layouts` folder for a the `page` layout, and if none exists, will use your theme's `page` layout.

### Stylesheets

Your theme's stylesheets should be placed in your theme's `/_sass` folder, again, just as you would when authoring a Jekyll site. Your theme's styles can be included in the user's stylesheet using the `@import` directive.

### Documenting your theme

Your theme should include a `/README.md` file, which explains how site authors can install and use your theme. What layouts are included? What includes? Do they need to add anything special to their site's configuration file?

### Adding a screenshot

Themes are visual. Show users what your theme looks like by including a screenshot as `/screenshot.png` within your theme's repository where it can be retrieved programatically. You can also include this screenshot within your theme's documentation.

### Previewing your theme

To preview your theme as you're authoring it, it may be helpful to add dummy content in, for example, `/index.html` and `/page.html` files. This will allow you to use the `jekyll build` and `jekyll serve` commands to preview your theme, just as you'd preview a Jekyll site.

If you do preview your theme locally, be sure to add `/_site` to your theme's `.gitignore` file to prevent the compiled site from also being included when you distribute your theme.
{: .info .note}

### Publishing your theme

Themes are published via [RubyGems.org](https://rubygems.org). You'll need a RubyGems account, which you can [create for free](https://rubygems.org/sign_up).

1. First, package your theme, by running the following command, replacing `my-awesome-jekyll-theme` with the name of your theme:

        gem build my-awesome-jekyll-theme.gemspec

2. Next, push your packaged theme up to the RubyGems service, by running the following command, again replacing `my-awesome-jekyll-theme` with the name of your theme:

        gem push my-awesome-jekyll-theme-*.gem