Master Sword Blue on Master Chief
#00ffee on #507d2a
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
3.84:1
Large text only
Not AAA (7:1). Swapping the two colours gives the same number — the ratio does not know which is the text.
APCA
Lc -62.5
Clears Lc 60 — headlines and other larger text.
Light text on a darker ground — the negative sign is the polarity.
Colour difference
ΔE00 42.3
different colours
Above 10 — related only in the sense that both are colours.
What the text colour has to become
#d1fff9 is the nearest colour of the same hue that passes AA on #507d2a, at 4.50:1. Only the lightness moved, and some chroma was given up to stay inside sRGB — which is the point: your colour stays recognisably your colour.
And to someone missing a cone
protanopia
Ratio 4.08:1, ΔE00 39.9.
deuteranopia
Ratio 3.70:1, ΔE00 46.1.
tritanopia
Ratio 2.79:1, ΔE00 26.7.
The weakest of the three is tritanopia, where the two are ΔE00 26.7 apart against 42.3 for a trichromat — still clearly two colours.
Both colours have pages of their own: Master Sword Blue ·Master Chief · the same pair the other way round ·all pairs