Of course you can. Don't be daft.

There are plenty of advantages to relative sizing, and in general it's a good policy, but there are many excellently-designed web sites whose sizes are absolute – just as there are many shit designs that're responsive as hell.

Eveytime I open a website with absolute sizes I want to cry. Most of my monitors have either crappy or too big resolutions.

Yeah, I am the sole developer so right now it is great for mockups and layouts. But demand the features you want, and I'll work towards them! :)

I started with basic min/max widths, because that was the sizing I commonly used. Percentages are important also, which will be coming.

Plus our experimental logic/animation tool let's you do some pretty spiffy stuff: http://www.screenr.com/Z9o and should support media-query conditionals in the future!

You can set min/max width and percentages are coming soon.