Color

#666fcc

#666fcc
hex#666fcc
rgbrgb(102, 111, 204)
hslhsl(235, 50%, 60%)
oklchoklch(0.579 0.142 276.9)
Closest name: Flood (#6677bb)Relative luminance 0.1855

Colors that go with #666fcc

Charcoal, Sea Green and Amber lead the list. Each partner is a real named colour with the reason it works — a wheel relationship, a neutral that carries it, or a pairing lifted from a palette or brand system that actually shipped — and every pair opens in the palette tool.

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#ccc366

#66a2cc · #9166cc

#cc666e · #6ecc66

Split-complementary

Open in tool →

#cc9166 · #a2cc66

#cc66a1 · #ccc366 · #66cc91

Contrast

#666fcc as textRatioAAAA largeAAAFix
Aaon white
4.46:1failpassfail
  • AA: use #626bcb as the text (4.68:1)
  • AAA: use #404abf as the text (7.12:1)
  • AA: or shift the background to #050505 (4.57:1)
Aaon black
4.71:1passpassfail
  • AAA: use #8c93d9 as the text (7.29:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #666fcc as the background.

Brands using this color

Fonts for this mood

#666fcc reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #666fcc
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — direct_palette, edit_direction, check_palette, check_contrast — read-only, no key. Every direction it proposes comes with a /colors/d/… link: open it, lock what you like, paste the link back, and the agent edits rather than re-rolls.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #666fcc and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/666fcc-9e9cc4-df8d4e-241f2d-e9eef1?lock=0&style=vibrant

Want the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.

Machine-readable: color.md