[Monkeydad]

The real reason they did it was: in the 1970s, the colors did not show up accurately on TVs back then, so they started using the silver-green (real name of that color) pants to make them look better on TV.

However, those days of bad TVs are long gone and they still use that trainwreck of a uniform.

I have no valid explanation for trying to use every shade of blue known to man in the same uniform, but that's the reason behind the green pants.