Don’t use rgb(r, g, b) for colors; use rgba(#hex, alpha) instead rgba(r, g, b, alpha)

`rgb()` is as unreadable as `#hex` when it comes to color values, but the `#hex` values have better support in many graphic tools and are simply shorter to write. (I’d happily use `hsl()` and `hsla()`, but none of the apps I use acknowledges the format.)

To be consistent (and still write less code), use the Sass helper, `rgba(#hex, alpha)`, instead of the standard `rgba(r, g, b, alpha)` wherever possible for semi-transparent color values.