Input: csscompressor.compress("transition: background-color 1s linear 0ms;")
Expected output: 'transition:background-color 1s linear 0ms;'
Actual output: 'transition:background-color 1s linear 0;'

According to the MDN page on , omitting the unit is only valid for , so when I use csscompressor, the declaration containing the 0ms or 0s is ignored by both Firefox and Chrome.

The same case is for <frequency>, and probably a few of the other ones, I think. Omitting the unit used to be valid in CSS2, but breaks in CSS3 unfortunately.

This is a fairly simple fix (removing the m?s from _zero_fmt_spec_re), and I'll create a PR and some tests.