colors
Back to gallery

Lucid Stratus

#66c0fa
Notes

Lucid Stratus (#66C0FA) is a true azure with a cool character. It leans cool, sitting on the blue, green, and violet side of the wheel. Quiet and dependable, a fit for product UI and data visualization. Its HSL profile (204°, 94%, 69%) 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 orange. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#66c0fa
RGB
rgb(102, 192, 250)
HSL
hsl(204, 94%, 69%)
HWB
hwb(204 40% 2%)
OKLCH
oklch(77.5% 0.120 239.2)
P3
color(display-p3 0.4877 0.7445 0.9597)
HSV
hsv(204, 59%, 98%)
LAB
lab(74.46% -10.35 -36.73)
LCH
lch(74.46% 38.16 254.26)
CMYK
cmyk(59%, 23%, 0%, 2%)

Etymology

Lucid
adjective

Latin lūcidus, clear / bright — derived from lūx (light). As a color modifier, lucid implies a clear-and-readable quality where the hue is unambiguous and free of optical clutter. Sits at the crisp-and-clear end of the grid, parallel to pellucid and plain in usage.

Stratus
noun

The Latin meteorological term for layer cloud — the low, gray-blue overcast clouds that cover the entire sky in mid-latitude winters. Stratus refers to a fully developed stratus deck on a North Sea winter morning: a soft, slightly muted deep blue-gray with the optical density of homogeneous low cloud.

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.

#66c0fa
Original
#a6c0fd
Protanopia
#91b1f9
Deuteranopia
#00cfd4
Tritanopia
#b1b1b1
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).
Failon White
2.00:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAAon Black
10.49:1

Wide gamut

Display P3 representation

The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.

sRGB hex
sRGB hex
##66C0FA
Display P3
Display P3
color(display-p3 0.4877 0.7445 0.9597)
P3 has subtle headroomOKLCH chroma 0.120

Moderately saturated colors gain a small bump in P3 — the difference is usually visible side-by-side on wide-gamut hardware but won't change the character of the color.

Related Colors

Canvas