Inspect GreenYellow (#ADFF2F) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
GreenYellow
#ADFF2F
Black text reads best on this background, at 17.12:1.
GreenYellow is one of the 148 CSS named colors, and resolves to #ADFF2F in every browser. In numbers that is rgb(173, 255, 47) and hsl(84, 100%, 59%). Perceptually it is a very light, vivid color: OKLCH puts its lightness at 91% and its chroma at 0.233. It sits in the greens at 130 degrees of OKLCH hue, and reads as a cool color.
White text only reaches 1.23:1 here, so black text is the safer pairing at 17.12:1. Because it is this light, GreenYellow works best as a page or card background with dark text over it.
The closest CSS named colors to GreenYellow, measured with CIEDE2000, are Chartreuse (#7FFF00), LawnGreen (#7CFC00), Lime (#00FF00). If GreenYellow is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#ADFF2F
RGB
rgb(173, 255, 47)
HSL
hsl(84, 100%, 59%)
HWB
hwb(84 18% 0%)
CMYK
cmyk(32%, 0%, 82%, 0%)
LAB
lab(92.2 -46.41 80.45)
LCH
lch(92.2 92.88 119.98)
OKLCH
oklch(91.3% 0.2335 130.02)
WCAG asks for 4.5:1 between body text and its background. On #ADFF2F white text measures 1.23:1 and black text 17.12:1, so black clears it and white does not.
White text on GreenYellow
WCAG 2.2
1.23:1
APCA
Lc 12
Fails AA body text
Fails AAA body text
Fails AA large text
Black text on GreenYellow
WCAG 2.2
17.12:1
APCA
Lc 92
Passes AA body text
Passes AAA body text
Passes AA large text
Check GreenYellow against any other color in the contrast checker.
GreenYellow sits at 91% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #EFFFE0 and down to #030800, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#BCFF6E
20% lighter
#CAFF93
40% lighter
#D7FFB0
60% lighter
#E3FFCA
80% lighter
#EFFFE0
100% lighter
#83C700
20% darker
#5E9000
40% darker
#3B5E00
60% darker
#1C2F00
80% darker
#030800
100% darker
Build a full accessible scale from #ADFF2F in the shade generator.
Hues rotated around #ADFF2F in OKLCH, then pulled back into the sRGB gamut. Each swatch is labelled with the nearest CSS named color so you have a keyword to start from.
GreenYellow sits at 130 degrees. Rotating it a half turn lands on 310 degrees, the hue directly opposite. It is the strongest pairing you can make without changing lightness, and the one most likely to vibrate if you use both at full chroma.
The neighbors of GreenYellow at 100 and 160 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
130, 250 and 10 degrees divide the wheel into thirds. Balanced enough to carry a whole palette without one color dominating the other two.
Instead of the complement at 310 degrees, this pair flanks it at 280 and 340. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around GreenYellow on the color wheel.
The biggest shift is under achromatopsia, where #ADFF2F reads as #DEDFDE, 30.3 CIEDE2000 units away. If GreenYellow is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#FFE125
Deuteranopia
#FFDE36
Tritanopia
#BDE7BF
Achromatopsia
#DEDFDE
The nearest CSS keywords to #ADFF2F, ranked by perceptual distance rather than by how close their hex digits happen to look.