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Heartening Creep Lagoon

#37b5d9
Notes

Heartening Creep Lagoon (#37B5D9) 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°, 68%, 53%) 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
#37b5d9
RGB
rgb(55, 181, 217)
HSL
hsl(193, 68%, 53%)
HWB
hwb(193 22% 15%)
OKLCH
oklch(72.1% 0.118 221.5)
P3
color(display-p3 0.3710 0.7000 0.8356)
HSV
hsv(193, 75%, 85%)
LAB
lab(68.65% -22.13 -27.90)
LCH
lch(68.65% 35.61 231.58)
CMYK
cmyk(75%, 17%, 0%, 15%)

Etymology

Heartening
adjective

Old English heorte (heart) — present-participle of hearten. As a color modifier, heartening implies a clear-and-uplifting-and-encouraging quality where the hue carries the visual register of cheerful-encouraging color-tone. Sits at the crisp-and-cheerful end of the grid, parallel to welcoming and cheerful in usage.

Creep
modifier

Old English crēopan, to-move-slowly. As a color modifier, creep implies a slow-stealthy-and-spreading quality, the visual register of ivy-on-wall-and-mist-creep hand-slow-stealthy-and-spreading ivy-on-wall-and-mist-creep-and-spreading-shadow crept-and-slow-stealthy-and-spreading surfaces under ivy-on-wall-and-mist-creep-and-spreading-shadow ruined-cloister-and-river-valley-and-evening-meadow encroaching-light. Sits at the modifier-and-mood end of the grid, parallel to lurk and prowl in usage.

Lagoon
noun

A shallow body of saltwater partially or fully enclosed by a barrier — coral atoll lagoons in the Pacific, Venice's Laguna Veneta, the Florida Keys' backcountry. The color refers to the average reflectance of a calm tropical lagoon at midday: a saturated, slightly muted blue-green with the optical clarity of shallow water over white sand. Brighter than reef, cooler than aquamarine, with the postcard weight of a Pacific atoll seen from above.

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.

#37b5d9
Original
#a0b0db
Protanopia
#8aa1d9
Deuteranopia
#00c0c1
Tritanopia
#9d9d9d
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
2.39:1
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
8.77:1

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
##37B5D9
Display P3
Display P3
color(display-p3 0.3710 0.7000 0.8356)
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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