Complementary
Maximum contrast — logos, CTAs, bold pairs
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Reds
Stoplight
Psychology
This color universally signifies warning, danger, or a call to halt, triggering an instinctive response.
History & Origin
Its use as a signal color is deeply ingrained in modern society, standardized globally for traffic lights and emergency signage due to its high visibility and psychological impact.
Combinations
Harmonious pairings from this color. Click any swatch to copy.
Values & Conversions
Copy any format — sRGB, print, and perceptual OKLCH.
CSS
Accessibility
WCAG 2.2 contrast for the pairings designers use most.
Recommended
Readable body text at this size.
5.04:1AA
Use white text for body copy, labels, and controls.
✓ Small text✓ Large text
All pairings
Aa
White on color
5.04:1AA
Aa
Black on color
4.16:1AA Large
Aa
Color on white
5.04:1AA
Aa
Color on black
4.16:1AA Large
Variations
Shades, tints, and tones in 10% steps — built for real UI states.
Darker steps for hover, shadow, and pressed states.
Design token scale
50–950 ramp for systems workColor vision
How this color reads under common forms of color vision deficiency.
Similar colors
Perceptually closest named colors in the library.