Color brief · Indigo
#666AB2 (#666AB2) — practical notes
#666AB2 (#666ab2) sits in the indigo family at about 237° hue, 33% saturation, and 55% lightness. Contrast is 4.92:1 on white and 4.27:1 on black, so white labels read more clearly on the swatch itself. Nearest Tailwind token: slate-500 (approximation unless the hex is an official scale stop).
- supporting UI accents
- text or icons on a white canvas
On a black or near-black UI, #666ab2 is 4.27:1. Prefer it as a fill, border, or large heading rather than 16px copy.
Specs & accessibility references: W3C WCAG 2.1 contrast minimum · MDN CSS color values · CSS Color Module Level 4 · WebAIM contrast guide.
COLOR EXPLORER
THE ORIGINAL SWATCH#666AB2
100% opacity · sRGB
YOUR NEXT GREAT ACCENT
#666AB2
Explore the codes, find a readable pairing, and see how this color feels in a real design.
HEX
#666AB2RGB
rgb(102, 106, 178)HSL
hsl(237, 33%, 55%)PUT IT INTO PRACTICE
A color is only half the story.
Try it with another color before you commit.
MAKE ROOM FOR SOMETHING GOOD
A little color. A whole lot of possibility.
Selected text: #666AB2CONTRAST RATIO4.92:1
- AA · normal text
- Pass
- AA · large text
- Pass
- AAA · normal text
- Fail
Normal text: AA 4.5:1, AAA 7:1. Large text: AA 3:1 (24px regular or about 19px bold).
Against white4.92:1
Against black4.27:1
Results use the exact pair, at full opacity. WCAG contrast guidance ↗
A color worth keeping? Save it above or share it.
COPY. PASTE. CREATE.
Color codes
HEX
#666ab2
RGB
rgb(102, 106, 178)
HSL
hsl(237, 33%, 55%)
OKLCH
oklch(0.5533 0.111 279.7)
CMYK
cmyk(43%, 40%, 0%, 30%)
CSS variable
--color-666ab2: #666ab2;
CMYK is an approximate reference; print output depends on the color profile. HSV and CMYK are not CSS color functions.
OKLCH
Perceptual 50–950 scale
Generated in OKLCH from this hex. Not an official Tailwind scale unless the hex itself is a Tailwind token.
Palette
Tints & shades
Full scale from light tints through the base color into deep shades
Palette
Tints
Mixed toward white — soft backgrounds and highlights
Palette
Shades
Mixed toward black — depth, text, and emphasis
Palette
Tones
Mixed toward neutral grey — muted UI surfaces
Harmony
Complementary
Opposite on the color wheel for contrast
Harmony
Analogous
Neighbors that sit comfortably together
Harmony
Triadic
Evenly spaced triad for vibrant sets
Harmony
Split complementary
Base plus two accents beside the complement
Harmony
Monochromatic
Same hue, varied lightness and saturation
Export
Developer code
css
:root {
--color666ab2-1: #666ab2;
}Design systems
Nearest official tokens
An arbitrary HEX is not an official Tailwind, Material, or Bootstrap color. Distance is CIEDE2000.
Nearest Tailwind color
slate-500
Very different · ΔE 8.97 · #64748B
Nearest CSS named color
SlateBlue
Very different · ΔE 7.32 · #6A5ACD
Nearest Material color
indigo-400
Noticeably different · ΔE 3.5 · #5C6BC0
Nearest Bootstrap color
primary
Very different · ΔE 12.42 · #0D6EFD
Using this color
Where #666ab2 works
#666AB2 (#666ab2) sits in the indigo family at about 237° hue, 33% saturation, and 55% lightness. Contrast is 4.92:1 on white and 4.27:1 on black, so white labels read more clearly on the swatch itself. Nearest Tailwind token: slate-500 (approximation unless the hex is an official scale stop).
Sensible jobs for this swatch
- supporting UI accents
- text or icons on a white canvas
On a black or near-black UI, #666ab2 is 4.27:1. Prefer it as a fill, border, or large heading rather than 16px copy.
Family context: Intuition, depth, and sincerity. Common in enterprise software and thoughtful products. Common uses still include buttons, charts, and accents in the Indigo range — always verify the pair for this exact hex in the contrast checker.
Related
Similar & related colors
Nearby colors from the library by perceptual distance