the tag color for english site seem incorrect, the dark grey color is the background while the yellow colour is the foreground. This is contradictory to other sites which have the darker colours as the foreground and lighter colours as the background.
Current foreground:
(#F4ECE3)
Current Background: 
(#5E5E5E)
In comparison to Stackoverflow:
Foreground: 
Background: 
As you can see the darker colour is background on english, and vice versa on SO.
On the actual english site's CSS color:#5E5E5E and background-color:#F4ECE3 (IE the opposite of the API)
Also may I suggest that on the next [semi-]major API update the tag_foreground_color be changed to tag_text_color. Its more descriptive and, unlike SO where the tag border is the same color to the text, SE sites text color is different to the border color
