Love it when it works. Problem is that with this addon enabled, it breaks some pages such as Facebook. Hope the dev can fix it!

But i also would like to change the color and height of the line.

uninstalled, because it reproducibly breaks pages.

initial review was:
"Good! Replaces 'Scroll Progress' for me.
Would love to configure both width and colour of the Reading Bar, as the 'Loading Progress Bar' does."