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Bastioned Cosmos

#3f81ea
Notes

Bastioned Cosmos (#3F81EA) 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°, 80%, 58%) places it in the highly saturated band at a mid lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. 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
#3f81ea
RGB
rgb(63, 129, 234)
HSL
hsl(217, 80%, 58%)
HWB
hwb(217 25% 8%)
OKLCH
oklch(61.4% 0.172 259.4)
HSV
hsv(217, 73%, 92%)
LAB
lab(54.76% 14.28 -59.15)
LCH
lch(54.76% 60.85 283.58)
CMYK
cmyk(73%, 45%, 0%, 8%)

Etymology

Bastioned
adjective

Italian bastionato, fortified-with-bastions — past-participle of bastion, derived from bastia (fortified-tower). As a color modifier, bastioned implies a saturated-and-fortified-and-projecting quality, the deep-rich color of Vauban-period military-fortress star-fort projecting-bastion stone-architecture. Sits at the bold-and-fortified end of the grid, parallel to fortified and buttressed.

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

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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.

#3f81ea
Original
#4b8bee
Protanopia
#267ce8
Deuteranopia
#009aaa
Tritanopia
#7b7b7b
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
3.79:1
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
5.54:1

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