Color
#663f78
#663f78rgb(102, 63, 120)hsl(281, 31%, 36%)oklch(0.438 0.101 314.4)Colors that go with #663f78
Charcoal, Sea Green and Crimson 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 #663f78: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
complementaryshippedSea Green sits directly opposite #663f78 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Crimson #dc143c
shippedCrimson is paired with #663f78 in 4 real palettes, including Wells Fargo's brand system and Lenovo's brand system, as the lead colour.
Denim #1560bd
shippedDesigners have shipped Denim with #663f78: 5 real palettes, including Hinge's brand system and HP's brand system, as the accent.
Midnight Blue #191970
shipped4 real palettes, including First Snow and Microsoft's brand system put Midnight Blue beside #663f78, as that palette's text colour.
Royal Blue #4169e1
shippedRoyal Blue is paired with #663f78 in 6 real palettes, including Console Light and Stripe's brand system, as the lead colour.
Taupe #483c32
shippedTaupe is paired with #663f78 in 8 real palettes, including Dusk and Datadog's brand system, as that palette's text colour.
Teal #008080
split-complementshippedTeal is a split-complement of #663f78: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Real palettes that use #663f78
Tints & shades
Harmonies
Contrast
| #663f78 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 8.24:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 2.55:1 | fail | fail | fail |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #663f78 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 #663f78 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/663f78-ba9fc1-b6cb62-2d1f2c-ebe9f1?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