Color
#3f4b7d
#3f4b7drgb(63, 75, 125)hsl(228, 33%, 37%)oklch(0.427 0.084 272.2)Colors that go with #3f4b7d
Sea Green, 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.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #3f4b7d — 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 #3f4b7d's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Blue #0000ff
shipped7 real palettes, including CVS's brand system and Tesco's brand system put Blue beside #3f4b7d, as the supporting colour.
Cornflower Blue #6495ed
shippedDesigners have shipped Cornflower Blue with #3f4b7d: 4 real palettes, including Blue Mono and Blizzard's brand system, as the supporting colour.
Crimson #dc143c
shippedCrimson is paired with #3f4b7d in 12 real palettes, including Walgreens's brand system and Codecademy's brand system, as the lead colour.
Denim #1560bd
shippedDesigners have shipped Denim with #3f4b7d: 15 real palettes, including HP's brand system and Unilever's brand system, as the accent.
Goldenrod #daa520
shippedGoldenrod shows up next to #3f4b7d in 5 real palettes, including Sapphire & Gold and Open House, as the supporting colour.
White Smoke #f5f5f5
neutralWhite Smoke is the surface for #3f4b7d: a clean near-white with no warm cast, so the cool hue stays clear instead of drifting muddy.
Real palettes that use #3f4b7d
Tints & shades
Harmonies
Contrast
| #3f4b7d as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 8.35:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 2.51:1 | 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 #3f4b7d as the background.
Brands using this color
No public brand in the corpus uses this exact color yet. Extract a brand to add one.
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 #3f4b7d and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/3f4b7d-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