Color mismatches with other sites

[srawlins]

@parlough this might be up your alley. @kallentu and I were comparing dartdoc's light mode with our other properties and noticed some discrepencies:

	Text color	Link color	Link hover color	Font
api.dart.dev	rgb(17, 17, 17)	rgb(1, 117, 194)	rgb(19, 185, 253)	Roboto, sans-serif
api.flutter.dev	rgb(74, 74, 74)	rgb(19, 137, 253)	rgb(19, 185, 253)	Open Sans, Roboto
dart.dev/language	rgb(33, 33, 33)	rgb(25, 103, 210)	rgb(4, 56, 117)	Google Sans Text
docs.flutter.dev	rgb(33, 33, 33)	rgb(4, 104, 215)	rgb(3, 68, 140)	Google Sans Text

Note in particular the the hover color gets brighter for api.dart.dev, but gets darker for the other two properties. 🤷