Pixel Perfect Web Design

It can't be done.

I keep running into designers, users and even developers who think they can design a layout that will be exactly the same on everyone's computers.

Web browsers are not the same as Photoshop!

Lets count the ways:

1. Fonts - each user of your site could have a different version of the font you specified, or maybe they don't have it at all, or they are ignoring your font specifications altogether.
2. Margins - browsers render margins differently, sometimes versions of the same browser render margins differently.
3. Color - browsers render colors differently, just look at some of the trouble trying to make an IE/NN page where image colors match the browser specified color, especially outside of the “safe” range.
4. Dpi - Might be 72, 96 or something else.

These are just the areas I could think of right now, I know there are others.

So my advice - don't even try. And if someone asks you to, make sure you charge them a lot of money and set the due date to Jan 15, 2048.