If you look at the layout used generate this "site" you'll see this:
<!-- tmpl_if name='stylesheet' -->
<link rel="stylesheet" href="<!-- tmpl_var name='stylesheet' -->"
type="text/css" />
<!-- tmpl_else -->
<link rel="stylesheet" href="style.css" type="text/css" />
<!-- /tmpl_if -->
Here the code basically says:
- If there is a variable called "stylesheet" set then use it.
- Otherwise include the "style.css" link.
If you guessed you could then set a per-page stylesheet-variable you'd be correct.
This page contains a link to one:
title: Stylesheet Example
stylesheet: dark.css
----
..