Color

#3f576e

#3f576e
hex#3f576e
rgbrgb(63, 87, 110)
hslhsl(209, 27%, 34%)
oklchoklch(0.447 0.048 247.9)
Closest name: Deep Indigo (#4c567a)Relative luminance 0.09

Colors that go with #3f576e

Sienna, Blue 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.

Real palettes that use #3f576e

Tints & shades

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

Harmonies

Complementary

Open in tool →

#6e563f

#3f6e6d · #3f406e

#6e3f57 · #576e3f

Split-complementary

Open in tool →

#6e3f40 · #6e6d3f

#6d3f6e · #6e563f · #406e3f

Contrast

#3f576e as textRatioAAAA largeAAAFix
Aaon white
7.5:1passpasspassPasses AAA — no fix needed.
Aaon black
2.8:1failfailfail
  • AA: use #577998 as the text (4.59:1)
  • AAA: use #7d9ab5 as the text (7.16:1)
  • AA: or shift the background to #c9c9c9 (4.53:1)
  • AAA: or shift the background to #f7f7f7 (7:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3f576e as the background.

Brands using this color

mcpConnect your agent — build around #3f576e
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 #3f576e and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3f576e-9cacc4-df4e4e-1f212d-e9f1f1?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