Tips: Go to a colornumber, keep pushing on the left mouse-button and drag the mouse over the colornumbers, to see the colornumbers in the opposite color.   
On your keyboard: Ctrl and '+' = Zoom-in, Ctrl and '-' = Zoom-out. Click on the hex-colornumber for more lighter or darker colors.

Colorbrowser - Part 1 of 2 - from #FF FF FF to #80 00 00

Optional view : Black Text & White Background