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Hot Cascade

#21e3f3
Notes

Hot Cascade (#21E3F3) is a true cyan with a neon character. It sits at the high-saturation edge of its family. Use it sparingly, as signage, accent, or highlight against darker surfaces. Its HSL profile (185°, 90%, 54%) 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
#21e3f3
RGB
rgb(33, 227, 243)
HSL
hsl(185, 90%, 54%)
HWB
hwb(185 13% 5%)
OKLCH
oklch(83.7% 0.139 204.2)
P3
color(display-p3 0.4221 0.8773 0.9415)
HSV
hsv(185, 86%, 95%)
LAB
lab(82.77% -38.15 -20.39)
LCH
lch(82.77% 43.26 208.12)
CMYK
cmyk(86%, 7%, 0%, 5%)

Etymology

Hot
adjective

Old English hāt, of high temperature — applied metaphorically to color since the eighteenth century for warm hues at high saturation. Hot pink, hot red: the implication is luminous intensity combined with thermal warmth. Sits in the bright-and-warm corner of the grid, alongside burning and vivid.

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.

#21e3f3
Original
#cfd9f4
Protanopia
#b5c6f4
Deuteranopia
#00ede8
Tritanopia
#bbbbbb
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
1.57:1
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
13.35:1

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
##21E3F3
Display P3
Display P3
color(display-p3 0.4221 0.8773 0.9415)
P3 has subtle headroomOKLCH chroma 0.139

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