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Tenacious Yangtze

#3f81fb
Notes

Tenacious Yangtze (#3F81FB) is a true azure 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 (219°, 96%, 62%) 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 amber. For something softer, pull in its analogous neighbors on either side of the wheel.

HEX
#3f81fb
RGB
rgb(63, 129, 251)
HSL
hsl(219, 96%, 62%)
HWB
hwb(219 25% 2%)
OKLCH
oklch(62.6% 0.195 261.4)
HSV
hsv(219, 75%, 98%)
LAB
lab(55.81% 20.42 -66.90)
LCH
lch(55.81% 69.94 286.97)
CMYK
cmyk(75%, 49%, 0%, 2%)

Etymology

Tenacious
adjective

Latin tenāx, holding-fast — adjectival suffix -ous. As a color modifier, tenacious implies a saturated-and-clinging quality where the hue grips its substrate with stubborn pigmentation. Sits at the bold-and-resilient end of the grid, parallel to unyielding and adamant in usage.

Yangtze
noun

The Chinese Cháng Jiāng — the longest river in Asia and the third-longest in the world. Yangtze color refers to mid-depth Yangtze River water at the Three Gorges: a saturated, slightly cool deep blue with the optical complexity of glacier-fed Tibetan-Plateau-source river 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.

#3f81fb
Original
#398fff
Protanopia
#007ef9
Deuteranopia
#009eb2
Tritanopia
#7c7c7c
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
3.66:1
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
5.74:1

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