Color

#3f4288

#3f4288
hex#3f4288
rgbrgb(63, 66, 136)
hslhsl(238, 37%, 39%)
oklchoklch(0.414 0.114 278.3)
Closest name: darkslateblue (#483d8b)Relative luminance 0.0673

Colors that go with #3f4288

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.

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#88863f

#3f6688 · #613f88

#883f41 · #41883f

Split-complementary

Open in tool →

#88613f · #66883f

#883f66 · #88863f · #3f8861

Contrast

#3f4288 as textRatioAAAA largeAAAFix
Aaon white
8.95:1passpasspassPasses AAA — no fix needed.
Aaon black
2.35:1failfailfail
  • AA: use #6c6fbc as the text (4.64:1)
  • AAA: use #8f91cc as the text (7.09:1)
  • AA: or shift the background to #b8b8b8 (4.51:1)
  • AAA: or shift the background to #e6e6e6 (7.17:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3f4288 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

#3f4288 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3f4288
live endpoint

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.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #3f4288 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3f4288-9f9cc4-df944e-251f2d-e9edf1?lock=0&style=vibrant

Want the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.

Machine-readable: color.md