Even simpler:
Code:
body { margin: 0; }
About widows, orphans and bottom margin, there are different opinions. Widows and orphans control whether you prefer blank lines at the bottom of your page or possibly a single word at the top of your next paragraph (in printed books, it's usual to avoid breaking a paragraph between pages at its first or last line).
Bottom margin, that depends on the reader. If a reader has no "status bar" at the bottom of the screen, then you'd want a bottom margin for the same reason you want a top one. With bottom-margin: 0 the bottom line letters could touch the edge of the screen (or even be cropped if the font has long descenders extending beyond the character box). Although Jon likes to promote this "no bottom margin" view, I think it's cleaner to just have an even margin around all sides, so I usually have:
Code:
@page { margin: 2mm; }
body { margin: 0; }
and I don't think it causes a problem for anyone.