Inspect LightSeaGreen (#20B2AA) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
LightSeaGreen
#20B2AA
Black text reads best on this background, at 8.01:1.
LightSeaGreen is one of the 148 CSS named colors, and resolves to #20B2AA in every browser. In numbers that is rgb(32, 178, 170) and hsl(177, 70%, 41%). Perceptually it is a mid-toned, moderately saturated color: OKLCH puts its lightness at 69% and its chroma at 0.114. It sits in the cyans at 189 degrees of OKLCH hue, and reads as a cool color.
White text only reaches 2.62:1 here, so black text is the safer pairing at 8.01:1. 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 LightSeaGreen, measured with CIEDE2000, are DarkTurquoise (#00CED1), MediumTurquoise (#48D1CC), CadetBlue (#5F9EA0). If LightSeaGreen is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#20B2AA
RGB
rgb(32, 178, 170)
HSL
hsl(177, 70%, 41%)
HWB
hwb(177 13% 30%)
CMYK
cmyk(82%, 0%, 4%, 30%)
LAB
lab(65.49 -38.83 -6.92)
LCH
lch(65.49 39.44 190.1)
OKLCH
oklch(69.12% 0.1142 188.96)
WCAG asks for 4.5:1 between body text and its background. On #20B2AA white text measures 2.62:1 and black text 8.01:1, so black clears it and white does not.
White text on LightSeaGreen
WCAG 2.2
2.62:1
APCA
Lc 55
Fails AA body text
Fails AAA body text
Fails AA large text
Black text on LightSeaGreen
WCAG 2.2
8.01:1
APCA
Lc 53
Passes AA body text
Passes AAA body text
Passes AA large text
Check LightSeaGreen against any other color in the contrast checker.
LightSeaGreen sits at 69% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #E4FFFC and down to #000807, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#3EC5BC
20% lighter
#55D7CF
40% lighter
#6BEBE2
60% lighter
#7FFEF5
80% lighter
#E4FFFC
100% lighter
#008C85
20% darker
#006762
40% darker
#004440
60% darker
#002422
80% darker
#000807
100% darker
Build a full accessible scale from #20B2AA in the shade generator.
Hues rotated around #20B2AA 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.
LightSeaGreen sits at 189 degrees. Rotating it a half turn lands on 9 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 LightSeaGreen at 159 and 219 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
189, 309 and 69 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 9 degrees, this pair flanks it at 339 and 39. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around LightSeaGreen on the color wheel.
The biggest shift is under deuteranopia, where #20B2AA reads as #7E89AC, 27.4 CIEDE2000 units away. If LightSeaGreen is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#9DA0AA
Deuteranopia
#7E89AC
Tritanopia
#00BCAF
Achromatopsia
#929292
The nearest CSS keywords to #20B2AA, ranked by perceptual distance rather than by how close their hex digits happen to look.