Color

#183e53

#183e53
hex#183e53
rgbrgb(24, 62, 83)
hslhsl(201, 55%, 21%)
oklchoklch(0.347 0.056 235.9)
Closest name: Capital Blue (#1a4157)Relative luminance 0.0426

Colors that go with #183e53

Royal Blue, Teal and Sienna 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 →

#532d18

#18534a · #182153

#53183e · #3e5318

Split-complementary

Open in tool →

#531821 · #534a18

#4a1853 · #532d18 · #215318

Contrast

#183e53 as textRatioAAAA largeAAAFix
Aaon white
11.33:1passpasspassPasses AAA — no fix needed.
Aaon black
1.85:1failfailfail
  • AA: use #307da6 as the text (4.61:1)
  • AAA: use #4d9fcb as the text (7.14:1)
  • AA: or shift the background to #a6a6a6 (4.66:1)
  • AAA: or shift the background to #cccccc (7.06:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #183e53 as the background.

Brands using this color

Fonts for this mood

#183e53 reads as cool, dark, luxury. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #183e53
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 #183e53 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/183e53-9cb1c4-df4e62-1f222d-e9f1f0?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