Add custom theme support and the dzello theme

exampleSite/content/home/resources.md

@@ -17,7 +17,7 @@ weight = 40
 
 ---
 
-### Ready to use
+### Service-ready
 
 - Deploy to [Netlify](https://netlify.com/)
 - Edit with [Forestry](https://forestry.io/)

exampleSite/content/home/shortcodes/markdown.md

@@ -18,14 +18,14 @@ Many handy slide shortcuts and customizations are possible.
 
 ---
 
-<!-- .slide: data-background="blue" -->
+<!-- .slide: data-background="#FF4081" -->
 
 For example, an HTML comment can change the background color of a slide.
 
 ```
 {{</* markdown */>}}
-<!-- .slide: data-background="blue" -->
-# I'm a blue slide
+<!-- .slide: data-background="#FF4081" -->
+# I'm a colorful slide
 {{</* /markdown */>}}
 ```
 

exampleSite/content/home/usage.md

@@ -29,11 +29,22 @@ theme = "moon"
 highlight_theme = "zenburn"
 ```
 
-[Reveal themes](https://github.com/hakimel/reveal.js/#theming) ·
+[Reveal.js themes](https://github.com/hakimel/reveal.js/#theming) ·
 [highlight.js themes](https://highlightjs.org/static/demo/)
 
 ---
 
+## Custom Reveal.js theme
+
+Point to a file in the `static` directory.
+
+```toml
+[params.reveal_hugo]
+custom_theme = "themes/dzello.css"
+```
+
+---
+
 ## Configure Reveal.js
 
 Set **snakecase** versions of Reveal.js params, which will be passed to `Reveal.initialize`.