What's the difference between pixels and ems?

A pixel represents a dot on our screenEms depend on the default font size2em stands for twice the default font sizePixels are always better than ems

Swee-heet! While pixels are an absolute unit, ems depend on the default font size. In some cases, pixels are the better choice; in others, ems are better.

So close! While pixels are an absolute unit, ems depend on the default font size. In some cases, pixels are the better choice; in others, ems are better.