Just a quick note about sass. Let’s say you had the following in /public/stylesheets/sass/foo.sass:
body line-height:1.2em h1 color:red
This would render a blank document for /public/stylesheets/foo.css. You won’t get an error about it, you’ll just get a blank document. Here’s the thing, when you’re declaring a CSS property, you MUST put a space after the colon. Failing to do so will just wind up in parsing errors on the sass side.
I hope I’ve saved you some head scratching. 
