Color reference

#EFFF5A color reference

Clear Very Light Yellow-green

This is a clear, very light yellow-green under the deterministic OKLCH hue, lightness, and chroma ranges. Its closest standardized CSS named color is Yellow (#FFFF00), measured with straight-line OKLab distance.

Descriptive label
Clear Very Light Yellow-green
Recommended text
Black · 19.12:1
Relative luminance
0.906089
Build a palette from #EFFF5A in Palette Generator Convert #EFFF5A in Color Converter
Formats UI preview Contrast 50–900 scale Harmonies Matches Related colors Color vision Exports

Copyable values

#EFFF5A in common color formats

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

Color conversions for #EFFF5A
Format Value Action
HEX #EFFF5A
RGB rgb(239 255 90)
HSL hsl(66 100% 67.65%)
HSV hsv(66 64.71% 100%)
HWB hwb(66 35.29% 0%)
XYZ D65 color(xyz-d65 0.731995 0.906091 0.233064)
LAB lab(96.6209% -20.3281 73.3077)
LCH lch(96.6209% 76.074 105.4986)
OKLAB oklab(95.8889% -0.076528 0.166829)
OKLCH oklch(95.8889% 0.183544 114.642)

Real-world test

Try #EFFF5A 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 #EFFF5A with black text at 19.12:1.

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: 1.1:1 · 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 #EFFF5A Exact pair assessment Results for source text on white appear below.

On white

1.1:1

  • 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 #EFFF5A Exact pair assessment Results for source text on black appear below.

On black

19.12:1

  • 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

#EFFF5A 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 1.05:1. 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 #EFFF5A at 19.12:1. This validates only that text pair, not hover, focus, disabled, or adjacent-color states.

Distinctive accent

Palette role

Its OKLCH chroma of 0.1835 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 19.12:1. Always retest against the actual rendered background and text size.

Tested backgrounds

Foreground pairing comparison

#EFFF5A foreground contrast on tested backgrounds
Pair Background Contrast ratio
Black#000000 19.12:1
Hue Codex ink#10212B 15:1
White#FFFFFF 1.1:1
Hue Codex paper#FBFAF5 1.05:1
Soft neutral#F2EFE6 1.05:1
Check #EFFF5A 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 #EFFF5A Source
100
200
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 #EFFF5A 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 #EFFF5A
Complement Chroma fitted to sRGB

Analogous

Source #EFFF5A
Analogous −30° Chroma fitted to sRGB
Analogous +30° Chroma fitted to sRGB

Triadic

Source #EFFF5A
Triad +120° Chroma fitted to sRGB
Triad +240° Chroma fitted to sRGB

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 Very Light Yellow-green
Complement
Explore #EFFF5A 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

Yellow

#FFFF00

OKLab distance ×100: 3.34

Tailwind v4 default

lime-200

oklch(93.8% 0.127 124.321)

OKLab distance ×100: 6.56 · sRGB preview #D8F999

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#EFFF5A
Approx.

Protanopia

Red-vision deficiency approximation

Original#EFFF5A
Approx.

Deuteranopia

Green-vision deficiency approximation

Original#EFFF5A
Approx.

Tritanopia

Blue-yellow deficiency approximation

Original#EFFF5A
Approx.

Achromatopsia

Monochromatic-vision approximation

Test #EFFF5A 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: #EFFF5A;
  --color-on-primary: #000000;
  --color-primary-oklch: oklch(95.8889% 0.183544 114.642);
  --color-primary-50: #EFFF5A;
  --color-primary-100: #DCEB46;
  --color-primary-200: #C2D026;
  --color-primary-300: #A9B600;
  --color-primary-400: #919C00;
  --color-primary-500: #798200;
  --color-primary-600: #626A00;
  --color-primary-700: #4C5200;
  --color-primary-800: #373C00;
  --color-primary-900: #242700;
}

Tailwind v4 CSS-first theme

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

@import "tailwindcss";

@theme {
  --color-brand: #EFFF5A;
  --color-brand-foreground: #000000;
  --color-brand-50: #EFFF5A;
  --color-brand-100: #DCEB46;
  --color-brand-200: #C2D026;
  --color-brand-300: #A9B600;
  --color-brand-400: #919C00;
  --color-brand-500: #798200;
  --color-brand-600: #626A00;
  --color-brand-700: #4C5200;
  --color-brand-800: #373C00;
  --color-brand-900: #242700;
}

Tailwind v3 / legacy config

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

module.exports = {
  theme: {
    extend: {
      colors: {
        brand: {
          '50': '#EFFF5A',
          '100': '#DCEB46',
          '200': '#C2D026',
          '300': '#A9B600',
          '400': '#919C00',
          '500': '#798200',
          '600': '#626A00',
          '700': '#4C5200',
          '800': '#373C00',
          '900': '#242700',
          DEFAULT: '#EFFF5A',
          foreground: '#000000',
        },
      },
    },
  },
};

Sass variables

Semantic source, foreground, OKLCH, and scale variables.

$color-primary: #EFFF5A;
$color-on-primary: #000000;
$color-primary-oklch: oklch(95.8889% 0.183544 114.642);
$color-primary-50: #EFFF5A;
$color-primary-100: #DCEB46;
$color-primary-200: #C2D026;
$color-primary-300: #A9B600;
$color-primary-400: #919C00;
$color-primary-500: #798200;
$color-primary-600: #626A00;
$color-primary-700: #4C5200;
$color-primary-800: #373C00;
$color-primary-900: #242700;

Modern color-mix()

Static fallbacks followed by OKLab tint and shade declarations.

:root {
  --color-primary: #EFFF5A;
  --color-primary-tint: #C2D026;
  --color-primary-tint: color-mix(in oklab, var(--color-primary) 72%, white);
  --color-primary-shade: #4C5200;
  --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 Very Light Yellow-green",
    "hex": "#EFFF5A",
    "rgb": "rgb(239 255 90)",
    "oklch": "oklch(95.8889% 0.183544 114.642)",
    "recommendedText": "#000000",
    "scale": {
        "50": "#EFFF5A",
        "100": "#DCEB46",
        "200": "#C2D026",
        "300": "#A9B600",
        "400": "#919C00",
        "500": "#798200",
        "600": "#626A00",
        "700": "#4C5200",
        "800": "#373C00",
        "900": "#242700"
    }
}

Continue the decision

Use #EFFF5A 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 #EFFF5A in Color PickerStart with this exact color and white as the working background for role and accessibility decisions. Build a palette from #EFFF5A in Palette GeneratorUse this exact HEX as the seed for a deterministic, role-based palette. Check #EFFF5A on white in Contrast CheckerStart with this color as the foreground and white as the background, then test the real pair.