Can't discern between enabled and disabled checkboxes

[cjcenizal]

@elastic/kibana-design I keep clicking disabled checkboxes because I can't distinguish them from enabled:

How about removing them altogether?

[snide]

We talked about this today in the design meeting actually. @Adrian-J volunteered to give them a looksee.

For reference, these are all the states we need.

[cchaos]

..and focus states ;)