Color
#3f4c8d
#3f4c8drgb(63, 76, 141)hsl(230, 38%, 40%)oklch(0.439 0.108 272.7)Colors that go with #3f4c8d
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 #3f4c8d: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #3f4c8d — 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 #3f4c8d'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 #3f4c8d in 4 real palettes, including Warner Bros.'s brand system and McDonald's's brand system, as the accent.
Blue #0000ff
shipped6 real palettes, including CVS's brand system and Tesco's brand system put Blue beside #3f4c8d, as the supporting colour.
Crimson #dc143c
shippedCrimson is paired with #3f4c8d in 13 real palettes, including Walgreens's brand system and Wells Fargo's brand system, as the lead colour.
Firebrick #b22222
shippedDesigners have shipped Firebrick with #3f4c8d: 5 real palettes, including Campbell's's brand system and Datadog's brand system, as the supporting colour.
Midnight Blue #191970
shipped20 real palettes, including First Snow and Microsoft's brand system put Midnight Blue beside #3f4c8d, as that palette's text colour.
Real palettes that use #3f4c8d
Tints & shades
Harmonies
Contrast
| #3f4c8d as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 7.99:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 2.63:1 | 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 #3f4c8d as the background.
Brands using this color
No public brand in the corpus uses this exact color yet. Extract a brand to add one.
Fonts for this mood
#3f4c8d 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 #3f4c8d and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/3f4c8d-9c9ec4-df814e-231f2d-e9eef1?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