Color

#3f536e

#3f536e
hex#3f536e
rgbrgb(63, 83, 110)
hslhsl(214, 27%, 34%)
oklchoklch(0.437 0.051 256.1)
Closest name: Deep Indigo (#4c567a)Relative luminance 0.0837

Colors that go with #3f536e

Sienna, Cadet Blue and Crimson 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 →

#6e5a3f

#3f6b6e · #423f6e

#6e3f54 · #546e3f

Split-complementary

Open in tool →

#6e423f · #6b6e3f

#6e3f6b · #6e5a3f · #3f6e42

Contrast

#3f536e as textRatioAAAA largeAAAFix
Aaon white
7.85:1passpasspassPasses AAA — no fix needed.
Aaon black
2.67:1failfailfail
  • AA: use #5b789f as the text (4.63:1)
  • AAA: use #8198b6 as the text (7.1:1)
  • AA: or shift the background to #c4c4c4 (4.5:1)
  • AAA: or shift the background to #f2f2f2 (7.02:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3f536e as the background.

Brands using this color

mcpConnect your agent — build around #3f536e
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 #3f536e and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3f536e-9ca9c4-df5a4e-1f1f2d-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