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Why do web pages look narrower on Linux than on Windows?
I see that the question is simple, it's very strange for me to see the webpages narrower on Linux. With other Chromium browsers like Vivaldi, Maxthon, Chrome, Chromium and Mirodi I don't have that problem.
What's the origin of the problem or the different feature that make web pages look different?
I found the problem, I start Opera in Kubuntu and the origin is the DPI configuration. Opera works with 86 of DPI instead of 96 the others Chromiums browsers.
I used this command line:
Opera tries to determine your system's DPI settings (the other Chromium browsers do not).
In KDE, you can change this in KDE's control center via Application Appearance -> Fonts.