Inspect Green (#008000) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
Green
#008000
White text reads best on this background, at 5.14:1.
Green is one of the 148 CSS named colors, and resolves to #008000 in every browser. In numbers that is rgb(0, 128, 0) and hsl(120, 100%, 25%). Perceptually it is a mid-toned, moderately saturated color: OKLCH puts its lightness at 52% and its chroma at 0.177. It sits in the greens at 142 degrees of OKLCH hue, and reads as a cool color.
White text clears WCAG AA on a Green background at 5.14:1. That combination of lightness and chroma makes it a workable mid-tone, the kind of value that lands in the middle of a shade scale.
The closest CSS named colors to Green, measured with CIEDE2000, are ForestGreen (#228B22), DarkGreen (#006400), SeaGreen (#2E8B57). If Green is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#008000
RGB
rgb(0, 128, 0)
HSL
hsl(120, 100%, 25%)
HWB
hwb(120 0% 50%)
CMYK
cmyk(100%, 0%, 100%, 50%)
LAB
lab(46.28 -47.55 48.59)
LCH
lch(46.28 67.98 134.38)
OKLCH
oklch(51.98% 0.1769 142.5)
WCAG asks for 4.5:1 between body text and its background. On #008000 white text measures 5.14:1 and black text 4.09:1, so white clears it and black does not.
White text on Green
WCAG 2.2
5.14:1
APCA
Lc 80
Passes AA body text
Fails AAA body text
Passes AA large text
Black text on Green
WCAG 2.2
4.09:1
APCA
Lc 29
Fails AA body text
Fails AAA body text
Passes AA large text
Check Green against any other color in the contrast checker.
Green sits at 52% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #ECFFE9 and down to #000900, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#329D2E
20% lighter
#53BA4D
40% lighter
#71D86A
60% lighter
#90F788
80% lighter
#ECFFE9
100% lighter
#006500
20% darker
#004C00
40% darker
#003300
60% darker
#001D00
80% darker
#000900
100% darker
Build a full accessible scale from #008000 in the shade generator.
Hues rotated around #008000 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.
Green sits at 142 degrees. Rotating it a half turn lands on 322 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 Green at 112 and 172 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
142, 262 and 22 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 322 degrees, this pair flanks it at 292 and 352. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around Green on the color wheel.
The biggest shift is under protanopia, where #008000 reads as #876500, 30 CIEDE2000 units away. If Green is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#876500
Deuteranopia
#6E5605
Tritanopia
#007758
Achromatopsia
#5B5C5B
The nearest CSS keywords to #008000, ranked by perceptual distance rather than by how close their hex digits happen to look.