Inspect SeaGreen (#2E8B57) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
SeaGreen
#2E8B57
Black text reads best on this background, at 4.95:1.
SeaGreen is one of the 148 CSS named colors, and resolves to #2E8B57 in every browser. In numbers that is rgb(46, 139, 87) and hsl(146, 50%, 36%). Perceptually it is a mid-toned, moderately saturated color: OKLCH puts its lightness at 57% and its chroma at 0.119. It sits in the greens at 155 degrees of OKLCH hue, and reads as a cool color.
White text only reaches 4.25:1 here, so black text is the safer pairing at 4.95:1. 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 SeaGreen, measured with CIEDE2000, are ForestGreen (#228B22), Green (#008000), MediumSeaGreen (#3CB371). If SeaGreen is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#2E8B57
RGB
rgb(46, 139, 87)
HSL
hsl(146, 50%, 36%)
HWB
hwb(146 18% 45%)
CMYK
cmyk(67%, 0%, 37%, 45%)
LAB
lab(51.49 -37.86 19.58)
LCH
lch(51.49 42.63 152.66)
OKLCH
oklch(56.85% 0.1187 154.95)
WCAG asks for 4.5:1 between body text and its background. On #2E8B57 white text measures 4.25:1 and black text 4.95:1, so black clears it and white does not.
White text on SeaGreen
WCAG 2.2
4.25:1
APCA
Lc 74
Fails AA body text
Fails AAA body text
Passes AA large text
Black text on SeaGreen
WCAG 2.2
4.95:1
APCA
Lc 35
Passes AA body text
Fails AAA body text
Passes AA large text
Check SeaGreen against any other color in the contrast checker.
SeaGreen sits at 57% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #E9FFF0 and down to #000803, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#4AA56F
20% lighter
#65BF87
40% lighter
#80D9A1
60% lighter
#9BF5BB
80% lighter
#E9FFF0
100% lighter
#00703E
20% darker
#00532D
40% darker
#00381C
60% darker
#001F0D
80% darker
#000803
100% darker
Build a full accessible scale from #2E8B57 in the shade generator.
Hues rotated around #2E8B57 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.
SeaGreen sits at 155 degrees. Rotating it a half turn lands on 335 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 SeaGreen at 125 and 185 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
155, 275 and 35 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 335 degrees, this pair flanks it at 305 and 5. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around SeaGreen on the color wheel.
The biggest shift is under achromatopsia, where #2E8B57 reads as #737373, 24.3 CIEDE2000 units away. If SeaGreen is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#877B55
Deuteranopia
#756E5A
Tritanopia
#208B7B
Achromatopsia
#737373
The nearest CSS keywords to #2E8B57, ranked by perceptual distance rather than by how close their hex digits happen to look.