Cool Slate Palette

Roofing slate in overcast light — pure cool gray with the faintest blue, more restrained than steel-and-slate.

#2A2E35

slate dark

HSL 218° 12% 19%

13.6:1 on white

#454B54

slate mid-dark

HSL 216° 10% 30%

8.8:1 on white

#6B7280

slate gray

HSL 220° 9% 46%

4.8:1 on white

#9CA3AF

light slate

HSL 218° 11% 65%

2.5:1 on white

#E5E7EB

pale gray background

HSL 220° 13% 91%

1.2:1 on white

Using this palette

More restrained and evenly spaced than steel-and-slate, which pushes toward a harder, more metallic register — this is closer to actual quarried slate roofing tile under flat, overcast daylight, with a gentler blue undertone and a more standard, UI-friendly lightness progression. #2A2E35 and #454B54 both clear AAA against white; #9CA3AF sits at the edge for large text only. A safe, slightly-cooler alternative to cool-neutrals for design-system base grays where the brand wants a bit more visual weight than cool-neutrals' lighter overall register provides.