Color

#183a68

#183a68
hex#183a68
rgbrgb(24, 58, 104)
hslhsl(215, 63%, 25%)
oklchoklch(0.35 0.09 256.8)
Closest name: Aegean Blue (#1b416f)Relative luminance 0.0422

Colors that go with #183a68

Firebrick, Sea Green and Teal 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 →

#684618

#186168 · #1e1868

#681839 · #396818

Split-complementary

Open in tool →

#681e18 · #616818

#681861 · #684618 · #18681e

Contrast

#183a68 as textRatioAAAA largeAAAFix
Aaon white
11.39:1passpasspassPasses AAA — no fix needed.
Aaon black
1.84:1failfailfail
  • AA: use #3375d1 as the text (4.61:1)
  • AAA: use #6597dc as the text (7.01:1)
  • AA: or shift the background to #a3a3a3 (4.51:1)
  • AAA: or shift the background to #cccccc (7.09:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #183a68 as the background.

Brands using this color

Fonts for this mood

#183a68 reads as cool, vivid, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #183a68
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 #183a68 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/183a68-9ca8c4-df5d4e-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