Color
#421d9f
#421d9frgb(66, 29, 159)hsl(257, 69%, 37%)oklch(0.379 0.19 286.1)Colors that go with #421d9f
Royal Blue, Blue 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.
Royal Blue #4169e1
analogousshippedRoyal Blue is #421d9f'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 Zillow's brand system and Procter & Gamble's brand system put Blue beside #421d9f, as the lead colour.
Crimson #dc143c
shippedCrimson is paired with #421d9f in 7 real palettes, including Pepsi's brand system and Walgreens's brand system, as the supporting colour.
Denim #1560bd
shippedDesigners have shipped Denim with #421d9f: 4 real palettes, including Warbyparker's brand system and Unilever's brand system, as the accent.
Firebrick #b22222
shippedDesigners have shipped Firebrick with #421d9f: 4 real palettes, including Datadog's brand system and 3M's brand system, as the accent.
Midnight Blue #191970
shipped8 real palettes, including Kraken's brand system and Blue Mono put Midnight Blue beside #421d9f, as the lead colour.
Olive Green #808000
complementaryOlive Green sits directly opposite #421d9f 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 #421d9f: softer than #000 and cool enough to feel like part of the same palette.
Real palettes that use #421d9f
Tints & shades
Harmonies
Contrast
| #421d9f as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 11.01:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 1.91:1 | 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 #421d9f as the background.
Brands using this color
Fonts for this mood
#421d9f 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 #421d9f and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/421d9f-ac9cc4-dfc24e-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