Color
#231b74
#231b74rgb(35, 27, 116)hsl(245, 62%, 28%)oklch(0.303 0.144 277.4)Colors that go with #231b74
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 #231b74: softer than #000 and cool enough to feel like part of the same palette.
Steel Blue #4682b4
analogousshippedSteel Blue is #231b74'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 Alaska Airlines's brand system and Sketch's brand system put Blue beside #231b74, as the accent.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #231b74: 5 real palettes, including Purina Pro Plan's brand system and Blue Mono, as the accent.
Crimson #dc143c
shippedCrimson is paired with #231b74 in 5 real palettes, including Nintendo's brand system and Casper Sleep's brand system, as the supporting colour.
Denim #1560bd
shippedDesigners have shipped Denim with #231b74: 11 real palettes, including Bank of America's brand system and Panasonic's brand system, as the accent.
Royal Blue #4169e1
shippedRoyal Blue is paired with #231b74 in 8 real palettes, including Discord's brand system and Confluent's brand system, as the lead colour.
Olive Green #808000
complementaryOlive Green sits directly opposite #231b74 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Real palettes that use #231b74
Tints & shades
Harmonies
Contrast
| #231b74 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 14.19:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 1.48:1 | 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 #231b74 as the background.
Brands using this color
Fonts for this mood
#231b74 reads as cool, vivid, dark. 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 #231b74 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/231b74-a49cc4-dfa54e-261f2d-e9ecf1?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