Standardize text colors

Proposal

For text color we should switch from grays to black (or white) with opacity. That will help us even more with increasing contrast and improving accessibility, no matter the background color. This “technique” is documented in Google's Material Design, but it's also being used by Medium (for example).

Hierarchy/Source Google Material Design Medium
Primary rgba(0,0,0,.87) (Passes AAA) rgba(0,0,0,.80) (Passes AAA) This is equal to #333 over white
Secondary rgba(0,0,0,.54) (Passes AA) rgba(0,0,0,.60) (Passes AA)
Tertiary rgba(0,0,0,.38) (Fails) rgba(0,0,0,.44) (Passes AA for large text)

Original Proposal

Currently our body text is quite light. We currently use #5c5c5c in most places for our body text. To increase contrast, we can make our body text darker. This would also help when screens are set to maximum brightness. Some suggestions for a new body text color are #333 and #444.

Screen_Shot_2016-12-14_at_12.44.34_PM

cc @cperessini @pedroms @awhildy