Color

#12378c

#12378c
hex#12378c
rgbrgb(18, 55, 140)
hslhsl(222, 77%, 31%)
oklchoklch(0.37 0.148 263.2)
Closest name: Deep Space Royal (#223382)Relative luminance 0.0475

Colors that go with #12378c

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 →

#8c6712

#12748c · #2b128c

#8c1237 · #378c12

Split-complementary

Open in tool →

#8c2b12 · #748c12

#8c1274 · #8c6712 · #128c2b

Contrast

#12378c as textRatioAAAA largeAAAFix
Aaon white
10.76:1passpasspassPasses AAA — no fix needed.
Aaon black
1.95:1failfailfail
  • AA: use #3d70e6 as the text (4.66:1)
  • AAA: use #6f94ec as the text (7.12:1)
  • AA: or shift the background to #a8a8a8 (4.53:1)
  • AAA: or shift the background to #d1d1d1 (7.05:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #12378c as the background.

Brands using this color

Palettes built around it

Fonts for this mood

#12378c reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #12378c
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 #12378c and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/12378c-9ca3c4-df6e4e-211f2d-e9eff1?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