I used to work in front end development and one of the issues I became keen on a lot is designers arriving at low contrast UI elements. A lot of time mock-ups would seem good, but at runtime and with differing font renderings on different systems, issue would arise. I installed the latest beta last night to try some things out, and right away noticed that the new vanilla UI is much lower contrast in areas like the inspector pane. The font color, when rendered 100% without anti-aliasing, is #2F2F2F and the background is #9B9B9B. You can dial these values yourself into various free online accessibility-minded contrast checkers, like https://webaim.org/resources/contrastchecker/ and https://contrastchecker.com/, the latter of which feels much more strongly about this being a bad contrast ratio. Other menus, like the Hierarchy view and Project view have much more appropriate contrast ratios, but I still feel the slightly-darker background grey is harder to read.