change fonts after distro update (opensuse 42.2)

[TechnoTux <techno2055 yandex com>]

hi,
i've recently updated my opensuse linux distro from leap 42.1 to 42.2
which come with gnome ver 3.20.2 (the prev came with 3.16.2)

my problem is the fonts in the new distro looks small, dense and blurry and really hearts my eyes
as i spend all of my time looking at the computer screen
if you look at the following pics you will see the different between the two versions:
http://pasteboard.co/j2ncVQDhS.png
http://pasteboard.co/j2nVtDvxh.png

the gnome-tweak-tool shows fonts are the same in both versions which isn't true(i think):
http://pasteboard.co/j2oWHg1MD.png

my question is
1-how can i know the exact font name currently used(for ex:in firefox i can right click an element then chose 
inspect elemnet to know the font) ?
2-how can i set the font in 3.20 to look like the one in 3.16?
thanks