Layouts
Layouts are templates that wrap around your content. They allow you to have the source code for your template in one place so you don't have to repeat things like your navigation and footer on every page.
Layouts live in the _layouts directory. The convention is to have a base
template called default.html and have other layouts
inherit from this as needed. Jigyll looks for layouts in
your site's _layouts directory first, then in the active
theme's _layouts. The directory name can be changed with
the layouts_dir key in your config file.
Usage
The first step is to put the template source code in default.html.
content is a special variable — its value is the rendered content of the
post or page being wrapped.
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>{{ page.title }}</title>
<link rel="stylesheet" href="/css/style.css">
</head>
<body>
<nav>
<a href="/">Home</a>
<a href="/blog/">Blog</a>
</nav>
<h1>{{ page.title }}</h1>
<section>
{{ content }}
</section>
<footer>
© to me
</footer>
</body>
</html>
You have full access to the front matter of the origin — in the example
above, page.title comes from the page's front matter.
Next you need to specify what layout you're using in your page's front matter. You can also use front matter defaults to save you from having to set this on every page.
---
title: My First Page
layout: default
---
This is the content of my page
Layout bodies are processed as Liquid only — never as Markdown — and the page's content is already rendered by the time the layout wraps it.
Inheritance
Layout inheritance is useful when you want to add something to an existing layout for a portion of documents on your site. A common example of this is blog posts: you might want a post to display the date and author but otherwise be identical to your base layout.
To achieve this, create another layout which specifies your original layout
in its front matter. For example, this layout will live at
_layouts/post.html:
---
layout: default
---
<p>{{ page.date }} - Written by {{ page.author }}</p>
{{ content }}
Now posts can use this layout while the rest of the pages use the default.
Variables
You can set front matter in layouts too. The only difference is that when
you're using it in Liquid, you need to use the layout variable instead of
page. For example:
---
city: San Francisco
---
<p>{{ layout.city }}</p>
{{ content }}