Color

#666ec7

#666ec7
hex#666ec7
rgbrgb(102, 110, 199)
hslhsl(235, 46%, 59%)
oklchoklch(0.574 0.136 277.3)
Closest name: Flood (#6677bb)Relative luminance 0.181

Colors that go with #666ec7

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 →

#c7bf66

#669ec7 · #8e66c7

#c7666e · #6ec766

Split-complementary

Open in tool →

#c78e66 · #9ec766

#c7669e · #c7bf66 · #66c78e

Contrast

#666ec7 as textRatioAAAA largeAAAFix
Aaon white
4.55:1passpassfail
  • AAA: use #434db6 as the text (7.06:1)
Aaon black
4.62:1passpassfail
  • AAA: use #8c92d4 as the text (7.18:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #666ec7 as the background.

Brands using this color

Fonts for this mood

#666ec7 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #666ec7
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 #666ec7 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/666ec7-9e9cc4-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