Cyantific on Hint of Blue
#77c9c2 on #cee1f2
Body text at this size
And the smaller size most interfaces actually use for paragraphs — the size that decides whether a pair is usable.
Caption text, which almost nothing passes.
WCAG 2.1
1.44:1
Fails AA
Not AAA (7:1). Swapping the two colours gives the same number — the ratio does not know which is the text.
APCA
Lc 17.6
Clears Lc 15 — disabled or purely decorative text, which is not meant to be read.
Dark text on a lighter ground.
Colour difference
ΔE00 19.6
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#0f6f69 is the nearest colour of the same hue that passes AA on #cee1f2, at 4.50:1. Only the lightness moved — which is the point: your colour stays recognisably your colour.
And to someone missing a cone
protanopia
Ratio 1.36:1, ΔE00 11.0.
deuteranopia
Ratio 1.48:1, ΔE00 10.0.
tritanopia
Ratio 1.58:1, ΔE00 15.0.
The weakest of the three is deuteranopia, where the two are ΔE00 10.0 apart against 19.6 for a trichromat — still two colours, but a closer call than it looks to you.
Both colours have pages of their own: Cyantific ·Hint of Blue · the same pair the other way round ·all pairs