Color
#666da9
#666da9rgb(102, 109, 169)hsl(234, 28%, 53%)oklch(0.555 0.093 277.8)Colors that go with #666da9
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.
Charcoal #36454f
neutralshippedCharcoal is the text near-black for #666da9: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #666da9 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Amber #ffbf00
shippedAmber is paired with #666da9 in 7 real palettes, including Lemon Squeezy's brand system and Wired's brand system, as the lead colour.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #666da9: 7 real palettes, including Fintech Trust and Glacier, as the lead colour.
Cornflower Blue #6495ed
shippedDesigners have shipped Cornflower Blue with #666da9: 4 real palettes, including Coca-Cola's brand system and NBA's brand system, as the supporting colour.
Crimson #dc143c
shippedCrimson is paired with #666da9 in 10 real palettes, including Marvel's brand system and Retro Pop, as the accent.
Firebrick #b22222
shippedDesigners have shipped Firebrick with #666da9: 5 real palettes, including AT&T's brand system and Campbell's's brand system, as the accent.
Goldenrod #daa520
shippedGoldenrod shows up next to #666da9 in 4 real palettes, including Open House and Sapphire & Gold, as the accent.
Real palettes that use #666da9
Tints & shades
Harmonies
Contrast
| #666da9 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 4.86:1 | pass | pass | fail |
|
Aaon black | 4.33:1 | fail | pass | fail |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #666da9 as the background.
Brands using this color
No public brand in the corpus uses this exact color yet. Extract a brand to add one.
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.
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
›analyze #666da9 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/666da9-9d9cc4-df8a4e-241f2d-e9eef1?lock=0&style=vibrantWant the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.
Machine-readable: color.md