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Resolute Cosmos

#3878df
Notes

Resolute Cosmos (#3878DF) is a true azure with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (217°, 72%, 55%) places it in the balanced band at a mid lightness. It works across type, buttons, and borders, saturated enough to feel deliberate but balanced enough to not fight the rest of the palette. For a confident two-color system, pair it with its complementary amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#3878df
RGB
rgb(56, 120, 223)
HSL
hsl(217, 72%, 55%)
HWB
hwb(217 22% 13%)
OKLCH
oklch(58.6% 0.170 259.6)
HSV
hsv(217, 75%, 87%)
LAB
lab(51.38% 14.98 -58.42)
LCH
lch(51.38% 60.31 284.38)
CMYK
cmyk(75%, 46%, 0%, 13%)

Etymology

Resolute
adjective

From the Latin resolutus, unwavering — used as a color modifier in literary contexts for hues that read as committed and unmoving. Resolute blue, resolute green: the saturation is full, the hue holds its position without shifting under different light. Sits in the bold-bucket center alongside strong and true, with slightly more focus on stability than presence.

Cosmos
noun

The Greek word for order — used in classical philosophy for the ordered universe and in modern English for the deep-space sky beyond Earth's atmosphere. Cosmos color refers to a long-exposure deep-space photograph: a saturated, slightly cool very deep blue with the optical depth of unfiltered upper-atmospheric scattering.

Closest matches

The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.

Variations

Click any swatch to explore

Harmonies

Accessibility

Color-vision simulation

How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.

#3878df
Original
#4183e3
Protanopia
#1673dd
Deuteranopia
#0090a1
Tritanopia
#727272
Achromatopsia
WCAG contrast

The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.

The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AA Largeon White
4.27:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
4.92:1

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