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Straightforward Reservoir

#21bcbf
Notes

Straightforward Reservoir (#21BCBF) 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 (181°, 71%, 44%) 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 red. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#21bcbf
RGB
rgb(33, 188, 191)
HSL
hsl(181, 71%, 44%)
HWB
hwb(181 13% 25%)
OKLCH
oklch(72.4% 0.118 197.0)
P3
color(display-p3 0.3522 0.7265 0.7426)
HSV
hsv(181, 83%, 75%)
LAB
lab(69.50% -35.82 -12.37)
LCH
lch(69.50% 37.89 199.06)
CMYK
cmyk(83%, 2%, 0%, 25%)

Etymology

Straightforward
adjective

English compound straight + forward — sharing root with German geradeaus. As a color modifier, straightforward implies a clear-and-direct-and-unencumbered quality where the hue carries the visual register of clear-aim-and-uncomplicated character. Sits at the crisp-and-honest end of the grid, parallel to candid and direct in usage.

Reservoir
noun

A constructed body of water — particularly the dam-impounded reservoirs of arid-region water supply: Lake Mead, Hetch Hetchy, Lake Powell. Reservoir color refers to mid-depth Lake Mead water: a saturated, slightly cool deep blue with the optical depth of stored desert water.

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.

#21bcbf
Original
#aeb3bf
Protanopia
#99a3c0
Deuteranopia
#00c3bd
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
9.01:1

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
##21BCBF
Display P3
Display P3
color(display-p3 0.3522 0.7265 0.7426)
P3 has subtle headroomOKLCH chroma 0.118

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.

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