User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:77.0) Gecko/20100101 Firefox/77.0
Steps to reproduce:
Hi, I have attached a screenshot of my Firefox reader mode experience on my 27", 1440p monitor.
The maximum width is what you see, and in my opinion it is a fraction of what it should be, (and I only use a small 27" monitor in 1440p so users with 4K or widescreen monitors probably have it even worse I assume).
Sorry, the sidebar thing didn't appear it the screenshot. Here you can see what I mean.
Bugbug thinks this bug should belong to this component, but please revert this change in case of error.