Nested properties in Sass

I have been using Sass for ages and I never realized I could do:

margin:
  top: 1em
  bottom: 2em

and have it compile to:

margin-top: 1em;
margin-bottom: 2em;

This is a great timesaver for all those background-image, margin, padding, border declarations.

Nesting several levels deep

It even allows deeper levels of nesting, so you can do:

border:
  top:
    style: dashed
    left:
      radius: 1em

to get:

border-top-style: dashed;
border-top-left-radius: 1em;

I guess that'll teach me to RTFM.