update the font-stack for Wikimedia Style Guide which gives preference to system typeface
Apple and Google both have better typeface alternatives available. 
They have better readability on screens and they have better language support.
This will deliver better native experience for readers. 
Proposed stack (see discussion for other links/suggestions)
font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Oxygen-Sans", Ubuntu, Cantarell, Lato, "Helvetica Neue", Helvetica, Arial, sans-serif;
This is the semantic order of things -
User device system preferred > Wikimedia Design preferred (Lato) > Helvetica > Arial > Generic
There's a known bug for Internet Explorer/Edge with this stack when used in font shorthand.
Can be circumvented when used only with font-family.
|Before||After (both on MacOS 10.13.4, Chrome 65.0.3325.181)|