cloudhead/less.js — comment on commit 624c297e7be093bd2234c4fac8d2bfa085cfadae
File:  line 0
By matthewdl:

Scratch that. In CSS, a comma is actually an ```or```. Such as in selectors or media queries. And is simply ```and```, such as in this example:

```
@media all and (max-width: 699px) and (min-width: 520px), (min-width: 1151px) {
body {
background: #ccc;
}
}
```

From: http://css-tricks.com/css-media-queries/

So, you'd not only be re-defining the comma operator, you'd actually be reversing it from CSS.