Tailwind CSS v3 color

Tailwind indigo-900 #312E81

Tailwind CSS v3's indigo-900 is #312E81. It is a dark soft blue in the blue family. In OKLCH it sits at lightness 0.359, chroma 0.135 and hue 278.7°. The nearest CSS named color is darkslateblue (#483D8B), ΔE2000 5.2 away.

Relative luminance
0.0419
OKLCH L · C · h
0.359 · 0.135 · 278.7
Best text
White 11.42:1
Hue family
Blue
Inspect this color Check contrast

#312E81 color codes

HEX
#312E81
RGB
rgb(49, 46, 129)
HSL
hsl(242, 47%, 34%)
OKLCH
oklch(0.359 0.135 278.7)
OKLab
oklab(0.359 0.020 -0.134)
CIELAB (D65)
L* 24.29, a* 27.64, b* -46.53
XYZ (D65)
X 6.20, Y 4.19, Z 21.25
CMYK (naive)
cmyk(62%, 64%, 0%, 49%)

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 #312E81 accessible?

White text on it reaches 11.42:1, passing AAA. Black text fails at 1.83:1.

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

    1.83:1

    • AA fails
    • AA large fails
    • AAA fails
    • APCA Lc +7

  • White text on it

    11.42:1

    • AA passes
    • AA large passes
    • AAA passes
    • APCA Lc −99

  • As text on black

    1.83:1

    • AA fails
    • AA large fails
    • AAA fails
    • APCA Lc 0

  • As text on white

    11.42:1

    • AA passes
    • AA large passes
    • AAA passes
    • APCA Lc +95

Nearest versions that pass 4.5:1

  • For text on white

    #312E81 11.42:1

    It already reaches 11.42:1 on white, so no change is needed.

  • For text on black

    #676CC5 4.52:1

    Lightening its OKLCH lightness from 0.36 to 0.57 reaches 4.52:1 on black, keeping the hue.

    Compare both in the Contrast System

Checking another pair? Use the Contrast Checker.

Studio

Adjust #312E81 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 #312E81

Eleven OKLCH lightness steps at this hue, each with its contrast against white and black. #312E81 sits at step 800.

  1. 50#F3F4FF
    White
    1.09
    Black
    19.19
  2. 100#E6EAFF
    White
    1.19
    Black
    17.57
  3. 200#CED4FF
    White
    1.44
    Black
    14.48
  4. 300#AFB7FF
    White
    1.90
    Black
    11.04
  5. 400#9098F3
    White
    2.63
    Black
    7.97
  6. 500#757BD6
    White
    3.77
    Black
    5.56
  7. 600#5F63BB
    White
    5.26
    Black
    3.98
  8. 700#4A4C9F
    White
    7.43
    Black
    2.82
  9. 800This color#312E81
    White
    11.42
    Black
    1.83
  10. 900#201C5F
    White
    15.07
    Black
    1.39
  11. 950#100842
    White
    18.49
    Black
    1.13

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

Tailwind CSS v3 indigo scale

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

  1. 50#EEF2FF
    White
    1.11
    Black
    18.78
  2. 100#E0E7FF
    White
    1.23
    Black
    17.04
  3. 200#C7D2FE
    White
    1.49
    Black
    14.07
  4. 300#A5B4FC
    White
    1.99
    Black
    10.53
  5. 400#818CF8
    White
    2.98
    Black
    7.04
  6. 500#6366F1
    White
    4.46
    Black
    4.70
  7. 600#4F46E5
    White
    6.28
    Black
    3.33
  8. 700#4338CA
    White
    7.90
    Black
    2.65
  9. 800#3730A3
    White
    9.93
    Black
    2.11
  10. 900This color#312E81
    White
    11.42
    Black
    1.83
  11. 950#1E1B4B
    White
    15.98
    Black
    1.31

Gamut

How vivid #312E81 can get

At its lightness and hue, sRGB reaches OKLCH chroma 0.219; #312E81 uses 62% of it. Display P3 reaches no further at this hue.

0.00.20.40.60.80.20.40.60.8 460480500520540560580600620
  • sRGB
  • Display P3
  • Rec. 2020
  • Dominant wavelength
OKLCH chroma
0.135
sRGB edge
0.219
Display P3 edge
0.222
Rec. 2020 edge
0.239
Dominant wavelength
463 nm
Excitation purity
67%
Chromaticity
x 0.1961, y 0.1325
  • This color#312E81
  • Most vivid in sRGB#3300AA
  • Most vivid in Display P3oklch(0.359 0.222 278.7)

On a screen without Display P3 the last tile shows the sRGB edge instead.

Use the wider color where screens show it
.accent {
  color: #312e81;
}
@media (color-gamut: p3) {
  .accent { color: color(display-p3 0.1801 0 0.6456); }
}

Mixing

Mixing #312E81

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%#9897C0
  • OKLab50%#8E94C2
  • OKLCH50%#8E94C2

Black #000000

  • sRGB50%#191741
  • OKLab50%#0C0B2E
  • OKLCH50%#0C0B2E

Its complement #473D00

  • sRGB50%#3C3641
  • OKLab50%#393B4D
  • OKLCH50%#004743
In CSS
/* A gradient and a mix, worked out in OKLCH */
background: linear-gradient(in oklch, #312e81, white);
color: color-mix(in oklch, #312e81 50%, white);

In use

#312E81 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, 4.5:111.42:1 Passes
  • Link and body-size textText, 4.5:111.42:1 Passes
  • Large headingLarge text, 3:111.42:1 Passes
  • Icons, borders and focus ringsNon-text, 3:111.42:1 Passes

Dark page

  • Button labelText, 4.5:111.42:1 Passes
  • Link and body-size textText, 4.5:11.63:1 Fails
  • Large headingLarge text, 3:11.63:1 Fails
  • Icons, borders and focus ringsNon-text, 3:11.63:1 Fails

For text on this page, the nearest shade that passes is #6F75CF 4.56:1

Color vision

How #312E81 looks with color blindness

Achromatopsia changes it most, ΔE2000 24.7; deuteranopia changes it least, 7.2.

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

    #003D84 ΔE2000 8.9

    Noticeable

    Reads as dark soft blue

  • Deuteranopia

    No working green (medium-wavelength) cones

    #00367F ΔE2000 7.2

    Noticeable

    Reads as dark soft blue

  • Tritanopia

    No working blue (short-wavelength) cones

    #004353 ΔE2000 17.6

    Distinct

    Reads as dark muted blue

  • Achromatopsia

    No cone color vision; lightness only

    #3A3A3A ΔE2000 24.7

    Distinct

    Reads as dark gray

Pairing check

Checked against its complement, #473D00. Their lightness contrast is only 1.05:1, so where hue collapses, add a label, icon or pattern.

VisionThe pairΔE2000Verdict
Normal vision#312E81 · #473D0051.1Stays distinct
Protanopia#003D84 · #453B0047.0Stays distinct
Deuteranopia#00367F · #473F0448.3Stays distinct
Tritanopia#004353 · #4E373332.7Stays distinct
Achromatopsia#3A3A3A · #3D3D3D1.0Easily confused

Harmony

Color harmonies for #312E81

Its complement is #473D00, a dark muted brown, on the warm side of the wheel.

Hue rotations in OKLCH, mapped into sRGB by trimming chroma so hue and lightness stay put.

Open the Harmony Studio
  • Base#312E81
  • Complement#473D00

Complementary

Open in Harmony Studio
  • −30°#003F6D
  • Base#312E81
  • +30°#512071

Analogous

Open in Harmony Studio
  • Base#312E81
  • +120°#6C1F00
  • +240°#00492C

Triadic

Open in Harmony Studio
  • Base#312E81
  • +150°#573400
  • +210°#2D4600

Split-complementary

Open in Harmony Studio

Code

Design tokens

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

CSS custom property

:root {
  --color-indigo-900: #312e81;
}

Tailwind config

// tailwind.config.js — already built in as indigo-900;
// pin the v3 value explicitly like this:
module.exports = {
  theme: {
    extend: {
      colors: {
        indigo: { 900: '#312e81' },
      },
    },
  },
};

Tailwind v4 theme

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

@theme {
  /* v4 has its own indigo-900; this pins the v3 value. */
  --color-indigo-900: oklch(0.359 0.135 278.7);
}

Design token (W3C DTCG)

{
  "color": {
    "indigo-900": {
      "$type": "color",
      "$value": {
        "colorSpace": "srgb",
        "components": [0.1922, 0.1804, 0.5059],
        "hex": "#312e81"
      },
      "$description": "Tailwind CSS v3 indigo-900"
    }
  }
}

SwiftUI color

import SwiftUI

enum Palette {
    static let indigo900 = Color(.sRGB, red: 0.192, green: 0.180, blue: 0.506, opacity: 1)
}

Jetpack Compose color

import androidx.compose.ui.graphics.Color

object Palette {
    val Indigo900 = Color(0xFF312E81)
}

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.

Neighbors

The eight nearest colors on this site by ΔE2000, closest first. Under 2 is hard to tell apart side by side.

Tools

Open #312E81 in the tools

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