[Xmonad] border colours

[Bruce Stephens]

I note that normalBorderColor is a grey, and focusedBorderColor is
red.  I don't find these particularly distinguishable.

Likely that's because I'm in the 10% or so of men who have red-green
colour blindness (I believe it's normally the red receptor that's
missing).

Not a big deal, since this is easily changed.  But maybe there's some
alternative that would be acceptable to almost everyone?  I find

focusedBorderColor = "#ff00ff"

to be nicely visible.  Maybe it's too obvious?