Color

#181b39

#181b39
hex#181b39
rgbrgb(24, 27, 57)
hslhsl(235, 41%, 16%)
oklchoklch(0.237 0.057 276.8)
Closest name: Nightwalker (#161d3b)Relative luminance 0.0127

Colors that go with #181b39

Charcoal, Dark Olive Green and Sea Green 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 →

#3a3718

#182c3a · #26183a

#3a181b · #1b3a18

Split-complementary

Open in tool →

#3a2618 · #2c3a18

#3a182c · #3a3718 · #183a26

Contrast

#181b39 as textRatioAAAA largeAAAFix
Aaon white
16.74:1passpasspassPasses AAA — no fix needed.
Aaon black
1.25:1failfailfail
  • AA: use #686fc0 as the text (4.62:1)
  • AAA: use #8c92cf as the text (7.13:1)
  • AA: or shift the background to #858585 (4.54:1)
  • AAA: or shift the background to #a8a8a8 (7.04:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #181b39 as the background.

Brands using this color

Palettes built around it

Fonts for this mood

#181b39 reads as cool, dark, luxury. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #181b39
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 #181b39 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/181b39-9e9cc4-df8d4e-241f2d-e9eef1?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