Add faded gradient overlays to the beginning and end of alternate lines
Adds a button floating on the bottom-right of the screen when on an AO3 page.
Clicking the button runs a script that adds gradients to each line in the current window configuration that fade between blue and orange to help improve readability. (If nothing happens, wait a few seconds and try again.)
Clicking again removes the added lines.
Clicking X removes the button from view (and also removes gradients)
If the window is modified, toggling the lines on again will reconfigure to the current view.
Some lines outside the proper content will also get gradients, but I don't care enough to figure out how to prevent it.
