Color

#5b78ec

#5b78ec
hex#5b78ec
rgbrgb(91, 120, 236)
hslhsl(228, 79%, 64%)
oklchoklch(0.61 0.177 269.9)
Closest name: Blue Öyster Cult (#5577ee)Relative luminance 0.2171

Colors that go with #5b78ec

Charcoal, Red and Sea Green 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 →

#eccf5b

#5bc0ec · #865bec

#ec5b78 · #78ec5b

Split-complementary

Open in tool →

#ec865b · #c0ec5b

#ec5bc0 · #eccf5b · #5bec86

Contrast

#5b78ec as textRatioAAAA largeAAAFix
Aaon white
3.93:1failpassfail
  • AA: use #4d6cea as the text (4.52:1)
  • AAA: use #1b43e4 as the text (7.07:1)
  • AA: or shift the background to #171717 (4.56:1)
Aaon black
5.34:1passpassfail
  • AAA: use #7b92ef as the text (7.2:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #5b78ec as the background.

Brands using this color

Fonts for this mood

#5b78ec reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #5b78ec
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 #5b78ec and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/5b78ec-9c9fc4-df7c4e-231f2d-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