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A grayish very dark blue, white text passes AA

Tailwind gray-900

Tailwind gray-900 is oklch(21% 0.034 264.665) in Tailwind CSS 4.3.3, which is #101828 in hex and rgb(16 24 40). White text on it reaches 17.75:1, passing WCAG AAA. Recolor (recolor.page) shows it on a real page below.

Last updated

#101828gray-900
From the theme file of Tailwind CSS 4.3.3 (--color-gray-900), converted with Recolor's color code, October 9, 2026
FormatValue
OKLCH, as Tailwind writes itoklch(21% 0.034 264.665)
Hex#101828
RGBrgb(16 24 40)
HSLhsl(220 43% 11%)
CSS variablevar(--color-gray-900)
Nearest CSS namemidnightblue #191970, 0.135 away in OKLab
White text17.75:1: AA passes, AAA passes, large text passes
Black text1.18:1: AA fails, AAA fails, large text fails

About gray-900

Tailwind gray-900 is a grayish very dark blue: OKLCH lightness 21.0%, chroma 0.034, hue 264.7 degrees. On Tailwind's gray scale it sits between gray-800 at 27.8% and gray-950 at 13.0%.

Its lightness is 11% in HSL and 21.0% in OKLCH, 10 points apart; only the second tracks how light it looks. Its value fits inside sRGB, so #101828 is the same color, not an approximation.

White text on gray-900 measures 17.75:1, past the 7:1 of WCAG AAA, while black text manages only 1.18:1. On the gray scale white text works from gray-500 to gray-950; gray-900 has 4 shades of margin.

CSS has no keyword in its neighborhood; midnightblue (#191970) is the nearest, a long 0.135 away in OKLab.

Tints and shades

  1. #d2d4d7
  2. #a6aab1
  3. #7c828c
  4. #555c69
  5. #313847
  6. #101828
  7. #0a101d
  8. #050913
  9. #020409
  10. #010103

From light to dark: 5 toward white and 4 toward black, mixed in OKLCH a sixth of the way at a time with the hue kept. A step that would repeat its neighbor is left out.

A palette around it

  1. #101828
  2. #a0c3e3
  3. #445800
  4. #ffebf4
  5. #cb7081

Recolor's generator, with gray-900 locked as swatch 1 and the seed taken from its hex, drew a triadic palette, three hues a third of the wheel apart: #a0c3e3, #445800, #ffebf4, #cb7081. Open it in Recolor.

Using gray-900

Pair it with text-white, 17.75:1; gray-900 as text on a white page measures the same ratio. In CSS it is var(--color-gray-900).

HTML
<a class="bg-gray-900 text-white" href="/start">Get started</a>
<p class="text-gray-900">Text in gray-900</p>

Common questions

Does white text pass WCAG AA on Tailwind gray-900?

Yes. White text measures 17.75:1 on gray-900, above the 4.5:1 that WCAG AA asks of body text, and above AAA's 7:1 too.

Is Tailwind gray-900 defined in OKLCH?

Yes. Tailwind CSS 4.3.3 defines it as --color-gray-900: oklch(21% 0.034 264.665); #101828 is its conversion to sRGB.

Is there a CSS named color for Tailwind gray-900?

No. The nearest CSS named color is midnightblue (#191970), 0.135 away in OKLab.

Sources