Inspect MediumBlue (#0000CD) in HEX, RGB, HSL, LCH and OKLCH, check its contrast, and copy the value you need.
MediumBlue
#0000CD
White text reads best on this background, at 11.16:1.
MediumBlue is one of the 148 CSS named colors, and resolves to #0000CD in every browser. In numbers that is rgb(0, 0, 205) and hsl(240, 100%, 40%). Perceptually it is a dark, vivid color: OKLCH puts its lightness at 38% and its chroma at 0.266. It sits in the blues at 264 degrees of OKLCH hue, and reads as a cool color.
White text clears WCAG AA on a MediumBlue background at 11.16:1, and AAA as well. At this chroma it is loud enough to be an accent or a call to action, but it will fight anything else vivid placed next to it.
The closest CSS named colors to MediumBlue, measured with CIEDE2000, are Blue (#0000FF), DarkBlue (#00008B), Navy (#000080). If MediumBlue is not quite right, those are the nearest keywords to try before reaching for a custom value.
HEX
#0000CD
RGB
rgb(0, 0, 205)
HSL
hsl(240, 100%, 40%)
HWB
hwb(240 0% 20%)
CMYK
cmyk(100%, 100%, 0%, 20%)
LAB
lab(22.66 57.93 -95.04)
LCH
lch(22.66 111.3 301.36)
OKLCH
oklch(38.35% 0.2657 264.05)
WCAG asks for 4.5:1 between body text and its background. On #0000CD white text measures 11.16:1 and black text 1.88:1, so white clears it and black does not.
White text on MediumBlue
WCAG 2.2
11.16:1
APCA
Lc 96
Passes AA body text
Passes AAA body text
Passes AA large text
Black text on MediumBlue
WCAG 2.2
1.88:1
APCA
Lc 11
Fails AA body text
Fails AAA body text
Fails AA large text
Check MediumBlue against any other color in the contrast checker.
MediumBlue sits at 38% OKLCH lightness. Holding its hue and chroma and moving only that value carries it up to #F5F9FF and down to #000220, which keeps the family recognizable instead of letting it drift toward gray the way a plain HSL ramp does.
#0B46F8
20% lighter
#457DFF
40% lighter
#80A9FF
60% lighter
#BBD2FF
80% lighter
#F5F9FF
100% lighter
#001C97
20% darker
#001477
40% darker
#000C58
60% darker
#00063B
80% darker
#000220
100% darker
Build a full accessible scale from #0000CD in the shade generator.
Hues rotated around #0000CD 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.
MediumBlue sits at 264 degrees. Rotating it a half turn lands on 84 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 MediumBlue at 234 and 294 degrees. They stay close enough to read as the same family, which is what you want for hover states, secondary surfaces and gradients.
264, 24 and 144 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 84 degrees, this pair flanks it at 54 and 114. You keep most of the contrast of a complementary pairing while losing the harshness.
Explore more combinations around MediumBlue on the color wheel.
The biggest shift is under achromatopsia, where #0000CD reads as #0F0F0F, 34.7 CIEDE2000 units away. If MediumBlue is the only thing marking a state or a series, roughly one viewer in twelve will miss it.
Protanopia
#0014D8
Deuteranopia
#000AC7
Tritanopia
#001E3E
Achromatopsia
#0F0F0F
The nearest CSS keywords to #0000CD, ranked by perceptual distance rather than by how close their hex digits happen to look.