LESS

It's time CSS was done right – LESS is leaner css.

Explained

LESS allows you to write CSS the way (I think) it was meant to, that is: with variables, nested rules and mixins!

Here's some example LESS code:

@dark: #110011;
.outline { border: 1px solid black }

.article {
    a { text-decoration: none }
    p { color: @dark }
    .outline;
}

And the CSS output it produces:

.outline { border: 1px solid black }
.article > a { text-decoration: none }
.article > p { color: #110011 }
.article { border: 1px solid black }

If you have CSS nightmares, just

$ lessc style.less