Ubuntu 18.04 LTS - bold font in the browsers
 

I use Ubuntu 18.04 LTS. After the system installation all fonts was fine. Currently I have a bold font in the browsers (firefox and chrome) on almost every website. Please take a look on the example screen shot. In other apps, for example qtcreator or gedit fonts looks fine. I have tried the following command but without success:
Do you have any idea how to fix that ?

How about CTRL and the minus combination which most browsers have to decrease zoom? Whereas the CTRL and plus combination will increase zoom.

I'm not sure that was horrible.

If you look at the Linux Questions site, some things are bold, others are not. Such as the thread title.

Are you saying that in your view this line of text is no different than other lines of text in my reply? I've made this line bold.

It's not related with zoom. Fonts on this forum looks fine, I see the difference in your text but for example on stackoverflow or google search result I see only bold font.

Weird.

So, per your font concern.

Perhaps you can get the information on various pages as to which fonts they are using and then check to see what's installed and if all is satisfied on your system.

I'm no expert on it, in fact many times I make big keyboard errors and I see some info/debug screen on my browser, I'm not sure if that shows the page fonts. ... Developer tools, CTRL-SHIFT-i Yeah! That's the one I hate happening! :) It does specify the fonts used.