CSS mix-blend-mode not working

[RyanScottLewis]

My theme uses mix-blend-mode: lighten; which works fine in Firefox and Chromium, but doesn't work in lightdm-webkit2-greeter

Software versions:

lightdm-webkit2-greeter 2.2.5-2
webkit2gtk              2.22.2-1
firefox                  62.0.2-1
chromium                69.0.3497.100-1

[NoiSek]

In my experience, the version of webkit used by gtk is closer to Safari than to Chromium. And it isn't particularly current, either. Make sure you test conservatively against Safari when developing themes.