Color

#3991ac

#3991ac
hex#3991ac
rgbrgb(57, 145, 172)
hslhsl(194, 50%, 45%)
oklchoklch(0.615 0.092 221.7)
Closest name: Blue Moon (#3992a8)Relative luminance 0.241

Colors that go with #3991ac

Charcoal, Copper and Crimson 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 →

#ac5439

#39ac8e · #3958ac

#ac3991 · #91ac39

Split-complementary

Open in tool →

#ac3958 · #ac8e39

#8e39ac · #ac5439 · #58ac39

Contrast

#3991ac as textRatioAAAA largeAAAFix
Aaon white
3.61:1failpassfail
  • AA: use #327e95 as the text (4.61:1)
  • AAA: use #255e6f as the text (7.22:1)
  • AA: or shift the background to #1f1f1f (4.57:1)
Aaon black
5.82:1passpassfail
  • AAA: use #40a2bf as the text (7.14:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3991ac as the background.

Brands using this color

No public brand in the corpus uses this exact color yet. Extract a brand to add one.

Fonts for this mood

#3991ac reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3991ac
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 #3991ac and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3991ac-9cb6c4-df4e72-1f242d-e9f1ef?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