Color

#3a78cb

#3a78cb
hex#3a78cb
rgbrgb(58, 120, 203)
hslhsl(214, 58%, 51%)
oklchoklch(0.573 0.143 256.6)
Closest name: Haddock’s Sweater (#277aba)Relative luminance 0.1864

Colors that go with #3a78cb

Charcoal, Copper and Amber 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 →

#cb8c3a

#3ac1cb · #433acb

#cb3a78 · #78cb3a

Split-complementary

Open in tool →

#cb433a · #c1cb3a

#cb3ac1 · #cb8c3a · #3acb43

Contrast

#3a78cb as textRatioAAAA largeAAAFix
Aaon white
4.44:1failpassfail
  • AA: use #3676c9 as the text (4.57:1)
  • AAA: use #295999 as the text (7.04:1)
  • AA: or shift the background to #080808 (4.51:1)
Aaon black
4.73:1passpassfail
  • AAA: use #6a99d7 as the text (7.15:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3a78cb as the background.

Brands using this color

Fonts for this mood

#3a78cb reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3a78cb
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 #3a78cb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3a78cb-9ca9c4-df5a4e-1f1f2d-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