Color
#21237d
#21237drgb(33, 35, 125)hsl(239, 58%, 31%)oklch(0.324 0.148 273.5)Colors that go with #21237d
Charcoal, Steel Blue and Blue 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 #21237d: softer than #000 and cool enough to feel like part of the same palette.
Steel Blue #4682b4
analogousshippedSteel Blue is #21237d's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Blue #0000ff
shipped5 real palettes, including Procter & Gamble's brand system and Alaska Airlines's brand system put Blue beside #21237d, as the supporting colour.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #21237d: 4 real palettes, including Purina Pro Plan's brand system and Blue Mono, as the accent.
Crimson #dc143c
shippedCrimson is paired with #21237d in 6 real palettes, including Casper Sleep's brand system and Nintendo's brand system, as the lead colour.
Denim #1560bd
shippedDesigners have shipped Denim with #21237d: 13 real palettes, including Bank of America's brand system and Panasonic's brand system, as the accent.
Orange Red #ff4500
shippedOrange Red is paired with #21237d in 4 real palettes, including Tide's brand system and NASA's brand system, as the accent.
Royal Blue #4169e1
shippedRoyal Blue is paired with #21237d in 9 real palettes, including Discord's brand system and Confluent's brand system, as the lead colour.
Real palettes that use #21237d
Tints & shades
Harmonies
Contrast
| #21237d as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 13.12:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 1.6:1 | 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 #21237d as the background.
Brands using this color
Fonts for this mood
#21237d 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 #21237d and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/21237d-a09cc4-df964e-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