Color
#3f2191
#3f2191rgb(63, 33, 145)hsl(256, 63%, 35%)oklch(0.366 0.17 286.9)Colors that go with #3f2191
Royal Blue, Blue and Denim 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.
Royal Blue #4169e1
analogousshippedRoyal Blue is #3f2191's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Blue #0000ff
shipped4 real palettes, including Procter & Gamble's brand system and Pepsi's brand system put Blue beside #3f2191, as the supporting colour.
Denim #1560bd
shippedDesigners have shipped Denim with #3f2191: 5 real palettes, including Google's brand system and Warbyparker's brand system, as the accent.
Steel Blue #4682b4
shippedDesigners have shipped Steel Blue with #3f2191: 4 real palettes, including Hershey's's brand system and Fintech Trust, as the accent.
Olive Green #808000
complementaryOlive Green sits directly opposite #3f2191 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Charcoal #36454f
neutralshippedCharcoal is the text near-black for #3f2191: softer than #000 and cool enough to feel like part of the same palette.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #3f2191: 3 real palettes, including Purina Pro Plan's brand system and Zillow's brand system, as the accent.
Crimson #dc143c
shippedCrimson is paired with #3f2191 in 3 real palettes, including Casper Sleep's brand system and Marvel's brand system, as the lead colour.
Real palettes that use #3f2191
Tints & shades
Harmonies
Contrast
| #3f2191 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 11.43:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 1.84:1 | 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 #3f2191 as the background.
Brands using this color
Fonts for this mood
#3f2191 reads as cool, vivid, technical. 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 #3f2191 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/3f2191-ab9cc4-dfbf4e-291f2d-e9ebf1?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