Tailwind CSS v3 color

Tailwind sky-50 #F0F9FF

Tailwind CSS v3's sky-50 is #F0F9FF. It is an off-white in the neutral family. In OKLCH it sits at lightness 0.977 with chroma 0.012, too low for hue to matter. The nearest CSS named color is aliceblue (#F0F8FF), ΔE2000 0.8 away.

Relative luminance: 0.9350
OKLCH L · C · h: 0.977 · 0.012 · 236.6
Best text: Black 19.69:1
Hue family: Neutral

Inspect this color Check contrast

#F0F9FF color codes

HEX: #F0F9FF
RGB: rgb(240, 249, 255)
HSL: hsl(204, 100%, 97%)
OKLCH: oklch(0.977 0.012 236.6)
OKLab: oklab(0.977 -0.007 -0.010)
CIELAB (D65): L* 97.43, a* -1.86, b* -3.90
XYZ (D65): X 87.86, Y 93.50, Z 108.01
CMYK (naive): cmyk(6%, 2%, 0%, 0%)

CIELAB and XYZ use the D65 white point; CSS lab() uses D50, so paste the OKLCH or HEX value into stylesheets. CMYK here is a plain formula with no press profile.

Legibility

Contrast: is #F0F9FF accessible?

Black text on it reaches 19.69:1, passing AAA. White text fails at 1.06:1.

WCAG 2 gives the same ratio whichever color is the text; APCA does not, so its Lc changes sign and size with polarity.

Open the Contrast System

Black text on it

19.69:1
- AA passes
- AA large passes
- AAA passes
- APCA Lc +101
White text on it

1.06:1
- AA fails
- AA large fails
- AAA fails
- APCA Lc 0
Text is here, unreadable at 1.06:1
As text on black

19.69:1
- AA passes
- AA large passes
- AAA passes
- APCA Lc −102
As text on white

1.06:1
- AA fails
- AA large fails
- AAA fails
- APCA Lc 0
Text is here, unreadable at 1.06:1

Nearest versions that pass 4.5:1

For text on white

#6E767C 4.62:1

Darkening its OKLCH lightness from 0.98 to 0.56 reaches 4.62:1 on white, keeping the hue.

Compare both in the Contrast System
For text on black

#F0F9FF 19.69:1

It already reaches 19.69:1 on black, so no change is needed.

Checking another pair? Use the Contrast Checker.

Studio

Adjust #F0F9FF live

Move lightness, chroma and hue in OKLCH, or drag on the map. The map is every lightness and chroma at the current hue: sRGB inside the solid area, Display P3 out to the dashed line.

The studio needs JavaScript.

Scale

Shades and tints of #F0F9FF

Eleven OKLCH lightness steps at this hue, each with its contrast against white and black. #F0F9FF sits at step 50.

50This color#F0F9FF

White
1.06
Black
19.69
100#E5ECF1

White
1.19
Black
17.59
200#D1D9DE

White
1.42
Black
14.69
300#B7BFC4

White
1.86
Black
11.26
400#9BA3A8

White
2.56
Black
8.19
500#7F878D

White
3.65
Black
5.75
600#687075

White
5.04
Black
4.16
700#52595E

White
7.12
Black
2.94
800#3A4145

White
10.38
Black
2.02
900#242A2D

White
14.54
Black
1.44
950#12171A

White
18.05
Black
1.16

Under each step, white and black text on it; a bold figure passes 4.5:1.

Tailwind CSS v3 sky scale

The real Tailwind palette, for comparison with the computed ramp above.

50This color#F0F9FF

White
1.06
Black
19.69
100#E0F2FE
White
1.14
Black
18.30
200#BAE6FD
White
1.32
Black
15.82
300#7DD3FC
White
1.66
Black
12.59
400#38BDF8
White
2.14
Black
9.80
500#0EA5E9
White
2.77
Black
7.57
600#0284C7
White
4.09
Black
5.12
700#0369A1
White
5.93
Black
3.53
800#075985
White
7.56
Black
2.77
900#0C4A6E
White
9.45
Black
2.22
950#082F49
White
13.87
Black
1.51

Gamut

How vivid #F0F9FF can get

A gray has no hue, so no gamut holds a more vivid version of #F0F9FF: more chroma would make it another color.

sRGB
Display P3
Rec. 2020
Dominant wavelength

OKLCH chroma: 0.012
sRGB edge: No hue
Display P3 edge: No hue
Rec. 2020 edge: No hue
Dominant wavelength: 483 nm
Excitation purity: 4%
Chromaticity: x 0.3036, y 0.3231

Mixing

Mixing #F0F9FF

Each row is the same mix worked out in a different space, with the halfway color at its end. sRGB, which older CSS gradients use, can sag gray or dark in the middle; OKLab keeps the lightness steps even; OKLCH holds chroma and hue as it goes.

White #FFFFFF

sRGB50%#F8FCFF
OKLab50%#F8FCFF
OKLCH50%#F8FCFF

Black #000000

sRGB50%#787D80
OKLab50%#5D6163
OKLCH50%#5D6163

In CSS

/* A gradient and a mix, worked out in OKLCH */
background: linear-gradient(in oklch, #f0f9ff, white);
color: color-mix(in oklch, #f0f9ff 50%, white);

In use

#F0F9FF in an interface

A button, a link, a heading, a focused field, an icon and a chart line in this color, on a light page and a dark one. Each check is a WCAG 2 contrast minimum: 1.4.3 for text, 1.4.11 for the rest.

Light page

Button labelText, 4.5:119.69:1 Passes
Link and body-size textText, 4.5:11.06:1 Fails
Large headingLarge text, 3:11.06:1 Fails
Icons, borders and focus ringsNon-text, 3:11.06:1 Fails

For text on this page, the nearest shade that passes is #6E767C 4.62:1

Dark page

Button labelText, 4.5:119.69:1 Passes
Link and body-size textText, 4.5:117.57:1 Passes
Large headingLarge text, 3:117.57:1 Passes
Icons, borders and focus ringsNon-text, 3:117.57:1 Passes

Color vision

How #F0F9FF looks with color blindness

As a neutral it barely changes under any simulation, ΔE2000 4.4 at most.

Simulated with Machado et al. (2009) at full severity, in linear light.

Simulate a whole page What each type sees

Protanopia

No working red (long-wavelength) cones

#F6F9FF ΔE2000 2.7

Close match

Reads as off-white
Deuteranopia

No working green (medium-wavelength) cones

#F4F7FF ΔE2000 3.2

Close match

Reads as off-white
Tritanopia

No working blue (short-wavelength) cones

#ECFBFB ΔE2000 4.4

Close match

Reads as off-white
Achromatopsia

No cone color vision; lightness only

#F8F8F8 ΔE2000 4.3

Close match

Reads as off-white

Pairing check

A near-neutral has no complementary hue to pair with, so tell it apart from neighboring grays by lightness contrast alone.

Harmony

Color harmonies for #F0F9FF

A neutral has no hue to rotate, so every harmony collapses back to the same gray. Pair it with an accent color instead.

Or pair it by lightness: steps of its own scale as text on it, and what each can carry.

Build a lightness scale in Harmony Studio

Step 950 #12171A · 16.93:1

Body text, AAA
Step 700 #52595E · 6.67:1

Body text, AA
Step 300 #B7BFC4 · 1.74:1

Decoration only, under 3:1

Code

Design tokens

Ready-to-paste tokens in six formats. Rename them to fit your system.

CSS custom property

:root {
  --color-sky-50: #f0f9ff;
}

Tailwind config

// tailwind.config.js — already built in as sky-50;
// pin the v3 value explicitly like this:
module.exports = {
  theme: {
    extend: {
      colors: {
        sky: { 50: '#f0f9ff' },
      },
    },
  },
};

Tailwind v4 theme

/* app.css — Tailwind CSS v4 */
@import "tailwindcss";

@theme {
  /* v4 has its own sky-50; this pins the v3 value. */
  --color-sky-50: oklch(0.977 0.012 236.6);
}

Design token (W3C DTCG)

{
  "color": {
    "sky-50": {
      "$type": "color",
      "$value": {
        "colorSpace": "srgb",
        "components": [0.9412, 0.9765, 1],
        "hex": "#f0f9ff"
      },
      "$description": "Tailwind CSS v3 sky-50"
    }
  }
}

SwiftUI color

import SwiftUI

enum Palette {
    static let sky50 = Color(.sRGB, red: 0.941, green: 0.976, blue: 1.000, opacity: 1)
}

Jetpack Compose color

import androidx.compose.ui.graphics.Color

object Palette {
    val Sky50 = Color(0xFFF0F9FF)
}

Matches

The nearest match in each system

The closest CSS name, Tailwind shade, RAL Classic paint and Crayola crayon by ΔE2000; under 2 is hard to tell apart side by side. RAL and Crayola values approximate physical colors.

Tools

Open #F0F9FF in the tools

Each opens over this page. More colors live in the Color Library, and every color page is listed on the hub.