Color
#666bd1
#666bd1rgb(102, 107, 209)hsl(237, 54%, 61%)oklch(0.574 0.154 278.3)Colors that go with #666bd1
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 #666bd1: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #666bd1 — 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 #666bd1 in 12 real palettes, including Wikipedia's brand system and Mastodon hosted on mastodon.social's brand system, as the accent.
Blue #0000ff
shipped14 real palettes, including Qualcomm's brand system and Pixar's brand system put Blue beside #666bd1, as the accent.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #666bd1: 12 real palettes, including Carrefour's brand system and Intel's brand system, as the accent.
Cornflower Blue #6495ed
shippedDesigners have shipped Cornflower Blue with #666bd1: 6 real palettes, including Mastodon hosted on mastodon.social's brand system and Coca-Cola's brand system, as the supporting colour.
Crimson #dc143c
shippedCrimson is paired with #666bd1 in 16 real palettes, including Marvel's brand system and Pizza Hut's brand system, as the accent.
Dark Orchid #9932cc
analogousshippedDark Orchid is #666bd1's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Real palettes that use #666bd1
Tints & shades
Harmonies
Contrast
| #666bd1 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 4.58:1 | pass | pass | fail |
|
Aaon black | 4.59:1 | pass | 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 #666bd1 as the background.
Brands using this color
Fonts for this mood
#666bd1 reads as cool, modern. The font library is tagged with the same vocabulary:
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 #666bd1 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/666bd1-9f9cc4-df924e-251f2d-e9edf1?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