Color

#3f599d

#3f599d
hex#3f599d
rgbrgb(63, 89, 157)
hslhsl(223, 43%, 43%)
oklchoklch(0.478 0.114 266.4)
Closest name: Blasphemous Blue (#3356aa)Relative luminance 0.1064

Colors that go with #3f599d

Charcoal, Sea Green 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.

Real palettes that use #3f599d

Tints & shades

Every swatch is its own page — click any to analyze it.

Harmonies

Complementary

Open in tool →

#9d823f

#3f889d · #533f9d

#9d3f59 · #599d3f

Split-complementary

Open in tool →

#9d533f · #889d3f

#9d3f88 · #9d823f · #3f9d53

Contrast

#3f599d as textRatioAAAA largeAAAFix
Aaon white
6.72:1passpassfail
  • AAA: use #3c5596 as the text (7.16:1)
Aaon black
3.13:1failpassfail
  • AA: use #5774bc as the text (4.63:1)
  • AAA: use #7f95cc as the text (7.07:1)
  • AA: or shift the background to #d4d4d4 (4.53:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3f599d 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

#3f599d reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3f599d
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 #3f599d and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3f599d-9ca3c4-df704e-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