Sass + SCSS overrides and overloads the [rgba() function](http://sass-lang.com/documentation/Sass/Script/Functions.html#rgba-instance_method) so it can also take parameters in the format `rgba($color, $alpha)`, e.g. `rgba(#000, .5)`.
It'd be pragmatic to leverage that overload and use hex colors that much more consistently in SCSS. If GitHub folks aren't writing much raw CSS this line can be trimmed further, ```* Use hex color codes `#000` (SCSS' `rgba()` function is overloaded to accept hex colors as a param, e.g., `rgba(#000, .5)`).``` (since Sass' overriding of `rgba()` isn't obvious perhaps good to spell it out explicitly here).
