Color

#3f63ab

#3f63ab
hex#3f63ab
rgbrgb(63, 99, 171)
hslhsl(220, 46%, 46%)
oklchoklch(0.509 0.122 262.8)
Closest name: Bellflower (#5d66aa)Relative luminance 0.1292

Colors that go with #3f63ab

Charcoal, Sea Green and Sienna 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 →

#ab873f

#3f99ab · #513fab

#ab3f63 · #63ab3f

Split-complementary

Open in tool →

#ab513f · #99ab3f

#ab3f99 · #ab873f · #3fab51

Contrast

#3f63ab as textRatioAAAA largeAAAFix
Aaon white
5.86:1passpassfail
  • AAA: use #375695 as the text (7.17:1)
Aaon black
3.58:1failpassfail
  • AA: use #5075be as the text (4.63:1)
  • AAA: use #7d98cf as the text (7.26:1)
  • AA: or shift the background to #e3e3e3 (4.57:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #3f63ab as the background.

Brands using this color

Fonts for this mood

#3f63ab reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #3f63ab
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 #3f63ab and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/3f63ab-9ca5c4-df694e-211f2d-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