Most currently used browsers support css. The ones that don't are several years old. Granted that you have to put in tweaks to cover browsers with a broken implementation of the CSS standard, but there's only a half dozen or so tweaks that you have to be aware of.
The convention among developers using CSS is to code to standards and then tweak for compatibility. IE seems to be the most broken browser and a lot of people code so it looks good in IE and then tweak for the other browsers. One day, MS will fix IE and bring it up to the standard and then their sites will be broken.
As far as the same look goes, even with tables for layout you run into browser discrepencies as different browsers display html elements different ways. - e.g. One browser pads a <p></p> tagset with 5 px of white space, another uses 10 px.
The web is not print media. The best you can do is to suggest a layout. It's up to the browser to determine how it actually displays it.