Use Ghostery, NoScript, or uBlock to disable Javascript/downloading certain files. Then add a rule for "*.css" to block any CSS being applied.
Optionally, without using any addons, disable Javascript under your Firefox settings. Then press press Alt to bring up your Menu Bar and under "View" go to "Page Style" and select "No Style". (Or "LeftAlt, Shift+V, Shift+Y, Shift+N")
Optionally, without using any addons, disable Javascript under your Firefox settings. Then press press Alt to bring up your Menu Bar and under "View" go to "Page Style" and select "No Style". (Or "LeftAlt, Shift+V, Shift+Y, Shift+N")
You may be interested in Readability: https://www.readability.com/addons