Tailwind CSS v3 color

Tailwind slate-700 #334155

Tailwind CSS v3's slate-700 is #334155. It is a dark grayish blue in the blue family. In OKLCH it sits at lightness 0.372, chroma 0.039 and hue 257.3°. The nearest CSS named color is darkslateblue (#483D8B), ΔE2000 11.4 away.

Relative luminance
0.0514
OKLCH L · C · h
0.372 · 0.039 · 257.3
Best text
White 10.35:1
Hue family
Blue
Inspect this color Check contrast

#334155 color codes

HEX
#334155
RGB
rgb(51, 65, 85)
HSL
hsl(215, 25%, 27%)
OKLCH
oklch(0.372 0.039 257.3)
OKLab
oklab(0.372 -0.009 -0.038)
CIELAB (D65)
L* 27.13, a* 0.12, b* -13.80
XYZ (D65)
X 4.89, Y 5.14, Z 9.33
CMYK (naive)
cmyk(40%, 24%, 0%, 67%)

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 #334155 accessible?

White text on it reaches 10.35:1, passing AAA. Black text fails at 2.02:1.

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

    2.02:1

    • AA fails
    • AA large fails
    • AAA fails
    • APCA Lc +9

  • White text on it

    10.35:1

    • AA passes
    • AA large passes
    • AAA passes
    • APCA Lc −98

  • As text on black

    2.02:1

    • AA fails
    • AA large fails
    • AAA fails
    • APCA Lc −8

  • As text on white

    10.35:1

    • AA passes
    • AA large passes
    • AAA passes
    • APCA Lc +94

Nearest versions that pass 4.5:1

  • For text on white

    #334155 10.35:1

    It already reaches 10.35:1 on white, so no change is needed.

  • For text on black

    #67768C 4.54:1

    Lightening its OKLCH lightness from 0.37 to 0.56 reaches 4.54:1 on black, keeping the hue.

    Compare both in the Contrast System

Checking another pair? Use the Contrast Checker.

Studio

Adjust #334155 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 #334155

Eleven OKLCH lightness steps at this hue, each with its contrast against white and black. #334155 sits at step 800.

  1. 50#EFF6FF
    White
    1.08
    Black
    19.29
  2. 100#DFECFF
    White
    1.19
    Black
    17.57
  3. 200#CAD9EF
    White
    1.43
    Black
    14.68
  4. 300#AFBFD6
    White
    1.86
    Black
    11.24
  5. 400#93A3BA
    White
    2.56
    Black
    8.18
  6. 500#78879E
    White
    3.64
    Black
    5.75
  7. 600#617086
    White
    5.03
    Black
    4.17
  8. 700#4B596D
    White
    7.12
    Black
    2.94
  9. 800This color#334155
    White
    10.35
    Black
    2.02
  10. 900#1E2939
    White
    14.67
    Black
    1.43
  11. 950#0D1623
    White
    18.16
    Black
    1.15

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

Tailwind CSS v3 slate scale

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

  1. 50#F8FAFC
    White
    1.04
    Black
    20.07
  2. 100#F1F5F9
    White
    1.09
    Black
    19.16
  3. 200#E2E8F0
    White
    1.23
    Black
    17.03
  4. 300#CBD5E1
    White
    1.48
    Black
    14.14
  5. 400#94A3B8
    White
    2.56
    Black
    8.19
  6. 500#64748B
    White
    4.75
    Black
    4.41
  7. 600#475569
    White
    7.57
    Black
    2.77
  8. 700This color#334155
    White
    10.35
    Black
    2.02
  9. 800#1E293B
    White
    14.62
    Black
    1.43
  10. 900#0F172A
    White
    17.85
    Black
    1.17
  11. 950#020617
    White
    20.17
    Black
    1.04

Gamut

How vivid #334155 can get

At its lightness and hue, sRGB reaches OKLCH chroma 0.134; #334155 uses 29% of it. Display P3, which many recent phones and laptops show, reaches 0.170 there: 27% more.

0.00.20.40.60.80.20.40.60.8 460480500520540560580600620
  • sRGB
  • Display P3
  • Rec. 2020
  • Dominant wavelength
OKLCH chroma
0.039
sRGB edge
0.134
Display P3 edge
0.170
Rec. 2020 edge
0.291
Dominant wavelength
477 nm
Excitation purity
28%
Chromaticity
x 0.2528, y 0.2655
  • This color#334155
  • Most vivid in sRGB#003C85
  • Most vivid in Display P3oklch(0.372 0.170 257.3)

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

Use the wider color where screens show it
.accent {
  color: #334155;
}
@media (color-gamut: p3) {
  .accent { color: color(display-p3 0 0.2119 0.5695); }
}

Mixing

Mixing #334155

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%#99A0AA
  • OKLab50%#939BA6
  • OKLCH50%#939BA6

Black #000000

  • sRGB50%#1A212B
  • OKLab50%#0D131C
  • OKLCH50%#0D131C

Its complement #4C3E28

  • sRGB50%#40403F
  • OKLab50%#404040
  • OKLCH50%#2B473C
In CSS
/* A gradient and a mix, worked out in OKLCH */
background: linear-gradient(in oklch, #334155, white);
color: color-mix(in oklch, #334155 50%, white);

In use

#334155 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, 4.5:110.35:1 Passes
  • Link and body-size textText, 4.5:110.35:1 Passes
  • Large headingLarge text, 3:110.35:1 Passes
  • Icons, borders and focus ringsNon-text, 3:110.35:1 Passes

Dark page

  • Button labelText, 4.5:110.35:1 Passes
  • Link and body-size textText, 4.5:11.80:1 Fails
  • Large headingLarge text, 3:11.80:1 Fails
  • Icons, borders and focus ringsNon-text, 3:11.80:1 Fails

For text on this page, the nearest shade that passes is #6F7F95 4.59:1

Color vision

How #334155 looks with color blindness

Tritanopia changes it most, ΔE2000 12.6; protanopia changes it least, 2.8.

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

    #3A4256 ΔE2000 2.8

    Close match

    Reads as dark grayish blue

  • Deuteranopia

    No working green (medium-wavelength) cones

    #363F55 ΔE2000 2.9

    Close match

    Reads as dark grayish blue

  • Tritanopia

    No working blue (short-wavelength) cones

    #284548 ΔE2000 12.6

    Distinct

    Reads as dark grayish teal

  • Achromatopsia

    No cone color vision; lightness only

    #404040 ΔE2000 10.5

    Distinct

    Reads as dark gray

Pairing check

Checked against its complement, #4C3E28. Their lightness contrast is only 1.00:1, so where hue collapses, add a label, icon or pattern.

VisionThe pairΔE2000Verdict
Normal vision#334155 · #4C3E2822.6Stays distinct
Protanopia#3A4256 · #443E2623.4Stays distinct
Deuteranopia#363F55 · #47412924.3Stays distinct
Tritanopia#284548 · #513A3825.7Stays distinct
Achromatopsia#404040 · #4040400.0Easily confused

Harmony

Color harmonies for #334155

Its complement is #4C3E28, a dark grayish 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#334155
  • Complement#4C3E28

Complementary

Open in Harmony Studio
  • −30°#294450
  • Base#334155
  • +30°#3F3D54

Analogous

Open in Harmony Studio
  • Base#334155
  • +120°#533839
  • +240°#364531

Triadic

Open in Harmony Studio
  • Base#334155
  • +150°#523A2E
  • +210°#424229

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-slate-700: #334155;
}

Tailwind config

// tailwind.config.js — already built in as slate-700;
// pin the v3 value explicitly like this:
module.exports = {
  theme: {
    extend: {
      colors: {
        slate: { 700: '#334155' },
      },
    },
  },
};

Tailwind v4 theme

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

@theme {
  /* v4 has its own slate-700; this pins the v3 value. */
  --color-slate-700: oklch(0.372 0.039 257.3);
}

Design token (W3C DTCG)

{
  "color": {
    "slate-700": {
      "$type": "color",
      "$value": {
        "colorSpace": "srgb",
        "components": [0.2, 0.2549, 0.3333],
        "hex": "#334155"
      },
      "$description": "Tailwind CSS v3 slate-700"
    }
  }
}

SwiftUI color

import SwiftUI

enum Palette {
    static let slate700 = Color(.sRGB, red: 0.200, green: 0.255, blue: 0.333, opacity: 1)
}

Jetpack Compose color

import androidx.compose.ui.graphics.Color

object Palette {
    val Slate700 = Color(0xFF334155)
}

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 #334155 in the tools

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