ubuntu 17.10 & Firefox DPI Scaling

Firefox has its own DPI mode, not always plays well in a desktop environment with modified DPI, yet the solution is simple:

First go to a firefox tab and type: "about:config", next in the search bar type: "layout.css.devPixelsPerPx" now change the Value to what you like.

If the decorations or the text is blurry, you may want to use a decimal value to make firefox more aesthetic, go for ".7". Or to make it bigger to a 2 or 1.5.

My screen is 15 inches 1080p; a value of 1.3 worked fine for me. The info came from this page:

https://fedoramagazine.org/how-to-get-firefox-looking-right-on-a-high-dpi-display-and-fedora/