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Straightforward Atoll

#178b58
Notes

Straightforward Atoll (#178B58) is a deep teal with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (154°, 72%, 32%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary magenta. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#178b58
RGB
rgb(23, 139, 88)
HSL
hsl(154, 72%, 32%)
HWB
hwb(154 9% 45%)
OKLCH
oklch(56.4% 0.126 157.9)
P3
color(display-p3 0.2550 0.5370 0.3619)
HSV
hsv(154, 83%, 55%)
LAB
lab(51.09% -43.01 18.82)
LCH
lch(51.09% 46.95 156.36)
CMYK
cmyk(83%, 0%, 37%, 45%)

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.

Atoll
noun

A ring-shaped coral reef enclosing a central lagoon — the geological signature of subsiding volcanic islands ringed by upward-growing coral. Atoll color refers to the unifying blue-green of a Maldivian-style atoll lagoon seen from above: a saturated, slightly cool deep blue-green with the optical clarity of shallow tropical 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.

#178b58
Original
#8a7f55
Protanopia
#7c765b
Deuteranopia
#008a7e
Tritanopia
#6f6f6f
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).
AA Largeon White
4.31:1
The quick brown foxSample body text at normal size. The wcag minimum for body contrast is 4.5:1 (AA) or 7:1 (AAA).
AAon Black
4.87:1

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
##178B58
Display P3
Display P3
color(display-p3 0.2550 0.5370 0.3619)
P3 has subtle headroomOKLCH chroma 0.126

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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