I feel exactly the same way. I had the experience of working with a designer on two projects, both of which he gave me pixel-perfect mockups for. One project was an iOS project, the other a web project. Getting the pixels to match up for the iOS project was fairly easy, just a matter of getting the right values for text shadow opacity, setting up stretched images, etc. The web project (which only had to run on newer WebKit browsers) was much harder. I was able to get a first draft very quickly, but getting every last pixel to match a mockup was a painful process to say the least. My takeaway was this: CSS is great for quickly developing styles, but when you need everything exactly perfect, it's a pain in the ass.