What is a pixel (px) in CSS?

Question

I am reading an ASP.NET book and it refers to CSS files and talks about pixels. But I never understood it from a resolution, layout, etc. point of view. For example, what does t

Answer 1

A pixel is a unit of measurement, at least, in regards to CSS. There is also pt, em, percentage... there are a few others. Each have their strengths.

W3schools is chock full of references, check the one on CSS.

I recommend downloading Firebug and experiment with changing the pixel width/height.