Color
#1b3bbb
#1b3bbbrgb(27, 59, 187)hsl(228, 75%, 42%)oklch(0.426 0.203 266)Colors that go with #1b3bbb
Charcoal, Sea Green and Steel 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 #1b3bbb: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #1b3bbb — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Steel Blue #4682b4
analogousshippedSteel Blue is #1b3bbb's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Amber #ffbf00
shippedAmber is paired with #1b3bbb in 5 real palettes, including Walmart's brand system and Binance's brand system, as the accent.
Blue #0000ff
shipped4 real palettes, including Procter & Gamble's brand system and Zillow's brand system put Blue beside #1b3bbb, as the supporting colour.
Cornflower Blue #6495ed
shippedDesigners have shipped Cornflower Blue with #1b3bbb: 7 real palettes, including Blue Mono and Gopro's brand system, as the supporting colour.
Crimson #dc143c
shippedCrimson is paired with #1b3bbb in 10 real palettes, including Behance's brand system and Chase's brand system, as the accent.
Dodger Blue #1e90ff
shippedDesigners have shipped Dodger Blue with #1b3bbb: 7 real palettes, including Coursera's brand system and Cargo's brand system, as the supporting colour.
Real palettes that use #1b3bbb
Tints & shades
Harmonies
Contrast
| #1b3bbb as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 8.79:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 2.39:1 | 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 #1b3bbb as the background.
Brands using this color
Fonts for this mood
#1b3bbb 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 #1b3bbb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/1b3bbb-9c9fc4-df7c4e-231f2d-e9eff1?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