Color reference

#42DEF7 color reference

Clear Light Cyan-blue

This is a clear, light cyan-blue under the deterministic OKLCH hue, lightness, and chroma ranges. Its closest standardized CSS named color is Sky Blue (#87CEEB), measured with straight-line OKLab distance.

Descriptive label
Clear Light Cyan-blue
Recommended text
Black · 13.02:1
Relative luminance
0.601162
Build a palette from #42DEF7 in Palette Generator Convert #42DEF7 in Color Converter
Formats UI preview Contrast 50–900 scale Harmonies Matches Related colors Color vision Exports

Copyable values

#42DEF7 in common color formats

Values are calculated from the same opaque sRGB color. Display rounding does not alter the internal calculations.

Color conversions for #42DEF7
Format Value Action
HEX #42DEF7
RGB rgb(66 222 247)
HSL hsl(188 91.88% 61.37%)
HSV hsv(188 73.28% 96.86%)
HWB hwb(188 25.88% 3.14%)
XYZ D65 color(xyz-d65 0.451536 0.601134 0.972221)
LAB lab(81.4103% -35.4732 -24.564)
LCH lch(81.4103% 43.1478 214.7013)
OKLAB oklab(83.1497% -0.11127 -0.066223)
OKLCH oklch(83.1497% 0.129485 210.7592)

Real-world test

Try #42DEF7 on interface components

Preview the source as a primary action, subtle status, form treatment, and card surface. Persistent state controls help touch and keyboard users inspect the same normal, hover, and active colors.

Normal state uses #42DEF7 with black text at 13.02:1.

Action

Primary button

Use the controls above or point to and press the button to inspect its visual states.

Status

Subtle alert badge

A 12% source tint over white provides the background; readable text is selected separately.

Ready for review

Form

Border and focus ring

Source ring on white: 1.61:1 · does not meet the 3:1 non-text threshold where applicable.

Surface

Card component

The selected state becomes the card surface with its strongest black-or-white text pairing.

Design system Color decision ready Review states and surrounding surfaces before shipping.

Accessibility diagnostics

WCAG contrast for exact color pairs

Each result applies only to the named foreground, background, text size, and requirement. It is not a complete accessibility or component-conformance claim.

Source #42DEF7 Exact pair assessment Results for source text on white appear below.

On white

1.61:1

  • Fail AA normal text · 4.5:1
  • Fail AAA normal text · 7:1
  • Fail AA large text · 3:1
  • Fail UI/non-text where applicable · 3:1
Source #42DEF7 Exact pair assessment Results for source text on black appear below.

On black

13.02:1

  • Pass AA normal text · 4.5:1
  • Pass AAA normal text · 7:1
  • Pass AA large text · 3:1
  • Pass UI/non-text where applicable · 3:1

Use guidance

What this color may be suitable for

Not recommended

Normal-sized text

#42DEF7 does not reach 4.5:1 on white or Hue Codex paper, so it should not be used there for normal-sized text.

Needs a boundary

Controls and interface graphics

Against Hue Codex paper, the color reaches only 1.54:1. Use a contrasting border or another non-color boundary for meaningful controls and graphics.

Readable pairing available

Colored surface or button fill

Black text provides the stronger black/white pairing on #42DEF7 at 13.02:1. This validates only that text pair, not hover, focus, disabled, or adjacent-color states.

Distinctive accent

Palette role

Its OKLCH chroma of 0.1295 gives it enough visual presence for an accent or primary role when the tested foreground and neighboring colors pass.

Pair available

Color used as foreground

The stronger black/white background is black at 13.02:1. Always retest against the actual rendered background and text size.

Tested backgrounds

Foreground pairing comparison

#42DEF7 foreground contrast on tested backgrounds
Pair Background Contrast ratio
Black#000000 13.02:1
Hue Codex ink#10212B 10.22:1
White#FFFFFF 1.61:1
Hue Codex paper#FBFAF5 1.54:1
Soft neutral#F2EFE6 1.4:1
Check #42DEF7 on another background in Contrast Checker

Design-system starting point

A perceptual 50–900 reference scale

The source color is preserved at the nearest lightness step. Other swatches keep its OKLCH hue, moderate chroma toward the extremes, and reduce chroma only when needed to remain in sRGB.

50
100
200 #42DEF7 Source
300
400
500
600
700
800
900

This is a Hue Codex reference scale, not a claim that the values match Tailwind, Material, or another framework’s named palette.

Adjust the #42DEF7 scale in Tints, Shades & Tones

Color relationships

Complementary, analogous, and triadic colors

Hue rotations use OKLCH while preserving lightness and requested chroma. When a rotated result falls outside sRGB, chroma is reduced deterministically and disclosed.

Complementary

Source #42DEF7
Complement Chroma fitted to sRGB

Analogous

Source #42DEF7
Analogous −30°
Analogous +30° Chroma fitted to sRGB

Triadic

Source #42DEF7
Triad +120°
Triad +240°

Applied pairing

A small interface check

The source anchors the main action while the complement marks a secondary status. Contrast is selected separately for each fill.

Project color Clear Light Cyan-blue
Complement
Explore #42DEF7 in Color Harmonies

Distance matching

Closest standardized and framework colors

Matches use straight-line OKLab distance ×100. A smaller value means the coordinates are closer in this model; it is not a claim that two tokens are interchangeable in a design system.

CSS named color

Sky Blue

#87CEEB

OKLab distance ×100: 5.71

Tailwind v4 default

cyan-300

oklch(86.5% 0.127 207.078)

OKLab distance ×100: 3.46 · sRGB preview #53EAFD

Print boundary

Pantone match not estimated

Reliable print matching needs licensed reference data plus a defined ink, paper, profile, and viewing condition.

Read the print methodology

Color-vision screening

Approximate color-vision-deficiency views

These encoded-sRGB matrix previews are screening approximations. They help reveal possible color-only distinctions but do not reproduce every person’s vision or establish accessibility conformance.

Original#42DEF7
Approx.

Protanopia

Red-vision deficiency approximation

Original#42DEF7
Approx.

Deuteranopia

Green-vision deficiency approximation

Original#42DEF7
Approx.

Tritanopia

Blue-yellow deficiency approximation

Original#42DEF7
Approx.

Achromatopsia

Monochromatic-vision approximation

Test #42DEF7 with a complete palette in the CVD Simulator

Ready to use

Copy framework-ready color tokens

Exports preserve the source, readable foreground, and generated 50–900 scale. Tailwind v4 CSS-first and Tailwind v3 JavaScript-config formats are labeled separately.

CSS custom properties

Semantic aliases and the complete 50–900 scale.

:root {
  --color-primary: #42DEF7;
  --color-on-primary: #000000;
  --color-primary-oklch: oklch(83.1497% 0.129485 210.7592);
  --color-primary-50: #E2FAFF;
  --color-primary-100: #96EEFF;
  --color-primary-200: #42DEF7;
  --color-primary-300: #16BFD7;
  --color-primary-400: #00A4B9;
  --color-primary-500: #008A9C;
  --color-primary-600: #00707F;
  --color-primary-700: #005763;
  --color-primary-800: #004049;
  --color-primary-900: #002A30;
}

Tailwind v4 CSS-first theme

Current @theme syntax for bg-brand, text-brand, and scale utilities.

@import "tailwindcss";

@theme {
  --color-brand: #42DEF7;
  --color-brand-foreground: #000000;
  --color-brand-50: #E2FAFF;
  --color-brand-100: #96EEFF;
  --color-brand-200: #42DEF7;
  --color-brand-300: #16BFD7;
  --color-brand-400: #00A4B9;
  --color-brand-500: #008A9C;
  --color-brand-600: #00707F;
  --color-brand-700: #005763;
  --color-brand-800: #004049;
  --color-brand-900: #002A30;
}

Tailwind v3 / legacy config

CommonJS theme.extend.colors for JavaScript-config projects.

module.exports = {
  theme: {
    extend: {
      colors: {
        brand: {
          '50': '#E2FAFF',
          '100': '#96EEFF',
          '200': '#42DEF7',
          '300': '#16BFD7',
          '400': '#00A4B9',
          '500': '#008A9C',
          '600': '#00707F',
          '700': '#005763',
          '800': '#004049',
          '900': '#002A30',
          DEFAULT: '#42DEF7',
          foreground: '#000000',
        },
      },
    },
  },
};

Sass variables

Semantic source, foreground, OKLCH, and scale variables.

$color-primary: #42DEF7;
$color-on-primary: #000000;
$color-primary-oklch: oklch(83.1497% 0.129485 210.7592);
$color-primary-50: #E2FAFF;
$color-primary-100: #96EEFF;
$color-primary-200: #42DEF7;
$color-primary-300: #16BFD7;
$color-primary-400: #00A4B9;
$color-primary-500: #008A9C;
$color-primary-600: #00707F;
$color-primary-700: #005763;
$color-primary-800: #004049;
$color-primary-900: #002A30;

Modern color-mix()

Static fallbacks followed by OKLab tint and shade declarations.

:root {
  --color-primary: #42DEF7;
  --color-primary-tint: #42DEF7;
  --color-primary-tint: color-mix(in oklab, var(--color-primary) 72%, white);
  --color-primary-shade: #005763;
  --color-primary-shade: color-mix(in oklab, var(--color-primary) 82%, black);
}

JSON design data

Source formats, readable text, and the generated scale.

{
    "name": "Clear Light Cyan-blue",
    "hex": "#42DEF7",
    "rgb": "rgb(66 222 247)",
    "oklch": "oklch(83.1497% 0.129485 210.7592)",
    "recommendedText": "#000000",
    "scale": {
        "50": "#E2FAFF",
        "100": "#96EEFF",
        "200": "#42DEF7",
        "300": "#16BFD7",
        "400": "#00A4B9",
        "500": "#008A9C",
        "600": "#00707F",
        "700": "#005763",
        "800": "#004049",
        "900": "#002A30"
    }
}

Continue the decision

Use #42DEF7 in a complete workflow

Reference values are a starting point. Test the color in its real role, background, states, typography, and surrounding palette before shipping.

Adjust #42DEF7 in Color PickerStart with this exact color and white as the working background for role and accessibility decisions. Build a palette from #42DEF7 in Palette GeneratorUse this exact HEX as the seed for a deterministic, role-based palette. Check #42DEF7 on white in Contrast CheckerStart with this color as the foreground and white as the background, then test the real pair.