Color

#183e81

#183e81
hex#183e81
rgbrgb(24, 62, 129)
hslhsl(218, 69%, 30%)
oklchoklch(0.378 0.121 260.8)
Closest name: Deep Space Royal (#223382)Relative luminance 0.0522

Colors that go with #183e81

Steel Blue, 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 →

#815b18

#187381 · #261881

#81183e · #3e8118

Split-complementary

Open in tool →

#812618 · #738118

#811873 · #815b18 · #188126

Contrast

#183e81 as textRatioAAAA largeAAAFix
Aaon white
10.27:1passpasspassPasses AAA — no fix needed.
Aaon black
2.04:1failfailfail
  • AA: use #3471da as the text (4.52:1)
  • AAA: use #6c98e4 as the text (7.25:1)
  • AA: or shift the background to #adadad (4.58:1)
  • AAA: or shift the background to #d6d6d6 (7.07:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #183e81 as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

Palettes built around it

Fonts for this mood

#183e81 reads as cool, vivid, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #183e81
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 #183e81 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/183e81-9ca6c4-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