A completely mental exercise!
Place the cursor over a colour name and left mouse button click to set the colour as
the background to the page. Move the cursor away from the colour name to
restore default background. Gradient examples are available where indicated
(not all are visibly effective) .
I have made all gradients run to White (but you don't have to).
Cursor over to apply gradient style, cursor out to reset. No mechanism (yet) for setting complimentary text
colours. Must make some sort of array for this, much too much redundant coding.
Somebody must have already made a script to do this!