Studio Does Not Recognize Some CSS Styles

I just added this ("-webkit-font-smoothing: antialiased;, text-rendering: optimizeLegibility;") to my custom css file and noticed it drew a line through it indicating it doesn't know these. Please make studio know every possible CSS styling.

Is there meant to be a comma after the semi colon in the first snip of CSS above? Maybe that's throwing it off and crossing it out