Q:

What do the different colours of accept rate mean?

Prompted by comments on this question.
I added the following comment

the accept rate is colour coded - Green == good, Grey == acceptable, Red == low

but I thought I ought to double check that a) this is accurate and b) complete.
The blog post that introduced the feature just states:

Certain visual styles will be applied to the percentage depending on how high or low it is. 

without any indication (that I can see) of what these styles are.
I don't think publicising the exact percentages is necessary just the colour == value.
@Ladybug Killer makes a very good point about colour blind or visually impaired users. While there is a tooltip which gives you the raw numbers (19 of 23 eligible questions) there isn't an indication that this is good, acceptable, poor or bad.

A:

The coloration of the accept rate is based purely on the percentage value, and nothing more. I'm not sure what to say about past observations otherwise, but I've confirmed internally (Thanks to Geoff Dalgas! Give him a hand!) that this is exactly how the code makes it. So I'm willing to chalk up any mis-readings (including my own from my previous answer) as "You were seeing things". ♪
At 35 or below, accept rate will be shown in increasingly deep shades of red and orange.
At 80 or above, accept rate will be shown in green hues.
At any value in between, accept rate will be grey.

