Color

#231d77

#231d77
hex#231d77
rgbrgb(35, 29, 119)
hslhsl(244, 61%, 29%)
oklchoklch(0.309 0.146 276.5)
Closest name: midnightblue (#191970)Relative luminance 0.0257

Colors that go with #231d77

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 →

#71771d

#1d4477 · #501d77

#77231d · #1d7723

Split-complementary

Open in tool →

#77501d · #44771d

#771d44 · #71771d · #1d7750

Contrast

#231d77 as textRatioAAAA largeAAAFix
Aaon white
13.87:1passpasspassPasses AAA — no fix needed.
Aaon black
1.51:1failfailfail
  • AA: use #6f67da as the text (4.63:1)
  • AAA: use #928ce3 as the text (7.08:1)
  • AA: or shift the background to #949494 (4.57:1)
  • AAA: or shift the background to #bababa (7.15:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #231d77 as the background.

Brands using this color

Fonts for this mood

#231d77 reads as cool, vivid, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #231d77
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 #231d77 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/231d77-a39cc4-dfa24e-261f2d-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