Switch Bedstead Web page to dark-on-light.

Switch Bedstead Web page to dark-on-light.

I recently saw Bedstead featured on a collection of programming fonts
and noticed that it was much prettier there than on its own Web page.
That's clearly wrong, and I think displaying it in a light colour on a
dark background (and with less than maximum contrast) helped.  The new
colours are based on my memory of the old Philips green-screen monitor
currently connected to my Beeb (because I'm too lazy to get out of bed
and check it).