Color

#3f4755

#3f4755
hex#3f4755
rgbrgb(63, 71, 85)
hslhsl(218, 15%, 29%)
oklchoklch(0.396 0.026 261.6)
Closest name: Abyssal (#404c57)Relative luminance 0.0622

Colors that go with #3f4755

Blue, Blush Pink and Cadet 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 →

#554d3f

#3f5255 · #423f55

#553f47 · #47553f

Split-complementary

Open in tool →

#55423f · #52553f

#553f52 · #554d3f · #3f5542

Contrast

#3f4755 as textRatioAAAA largeAAAFix
Aaon white
9.36:1passpasspassPasses AAA — no fix needed.
Aaon black
2.24:1failfailfail
  • AA: use #68768d as the text (4.56:1)
  • AAA: use #8d98aa as the text (7.2:1)
  • AA: or shift the background to #b5b5b5 (4.56:1)
  • AAA: or shift the background to #e0e0e0 (7.09:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3f4755 as the background.

Brands using this color

Fonts for this mood

#3f4755 reads as cool, muted, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3f4755
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 #3f4755 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3f4755-9ca6c4-df644e-201f2d-e9f0f1?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