Color
#663db3
#663db3rgb(102, 61, 179)hsl(261, 49%, 47%)oklch(0.474 0.178 294.6)Colors that go with #663db3
Charcoal, Royal Blue and Sea Green 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 #663db3: softer than #000 and cool enough to feel like part of the same palette.
Royal Blue #4169e1
analogousshippedRoyal Blue is #663db3's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Sea Green #2e8b57
split-complementshippedSea Green is a split-complement of #663db3: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Crimson #dc143c
shippedCrimson is paired with #663db3 in 9 real palettes, including Wells Fargo's brand system and Gemstone, as the lead colour.
Denim #1560bd
shippedDesigners have shipped Denim with #663db3: 9 real palettes, including Linkedin's brand system and Slack's brand system, as the lead colour.
Firebrick #b22222
shippedDesigners have shipped Firebrick with #663db3: 4 real palettes, including Datadog's brand system and Campbell's's brand system, as the accent.
Midnight Blue #191970
shipped10 real palettes, including Kraken's brand system and Paramount+'s brand system put Midnight Blue beside #663db3, as the lead colour.
Red #ff0000
shippedRed is paired with #663db3 in 4 real palettes, including Twitch's brand system and L'Oréal's brand system, as the accent.
Real palettes that use #663db3
Tints & shades
Harmonies
Contrast
| #663db3 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 7.28:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 2.88:1 | 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 #663db3 as the background.
Brands using this color
Fonts for this mood
#663db3 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 #663db3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/663db3-af9cc4-dfcb4e-2a1f2d-e9eaf1?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