This is just something I've wondered for awhile and is probably a very basic question

How do you 'tab' in the editor in the stylesheet section. When I edit the existing styles, they end up so messy I cannot read them because I haven't worked out to tab across. So half of it is neatly tabbed/indented with my additions just sitting there on the margin.
It's not a huge problem, but I like to be neat and tidy.

Thanks