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Bright Cascade

#21b8e3
Notes

Bright Cascade (#21B8E3) is a true cyan with a vibrant character. It holds its own as a focal accent, carrying visual weight without tipping into neon territory. Its HSL profile (193°, 78%, 51%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#21b8e3
RGB
rgb(33, 184, 227)
HSL
hsl(193, 78%, 51%)
HWB
hwb(193 13% 11%)
OKLCH
oklch(72.8% 0.130 223.5)
P3
color(display-p3 0.3451 0.7111 0.8727)
HSV
hsv(193, 85%, 89%)
LAB
lab(69.57% -22.37 -31.98)
LCH
lch(69.57% 39.03 235.02)
CMYK
cmyk(85%, 19%, 0%, 11%)

Etymology

Bright
adjective

Old English beorht, shining, luminous — cognate with the German Bracht, splendor. Applied to color since at least the medieval period for hues that read as luminous: not just light in value but optically active, as if scattering more light back than a dimmer color of the same lightness would. Sits at the bright-bucket center alongside vivid and brilliant.

Cascade
noun

A waterfall of moderate size — particularly the Cascade Range of waterfalls along the Pacific Northwest's Columbia River Gorge. Cascade color refers to the white-and-blue of falling water at Multnomah Falls: a soft, slightly cool pale blue-white with the optical complexity of mist-and-water in motion.

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.

#21b8e3
Original
#a0b4e5
Protanopia
#87a2e3
Deuteranopia
#00c5c6
Tritanopia
#9b9b9b
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
2.33:1
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
9.03:1

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
##21B8E3
Display P3
Display P3
color(display-p3 0.3451 0.7111 0.8727)
P3 has subtle headroomOKLCH chroma 0.130

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