Color

#313b87

#313b87
hex#313b87
rgbrgb(49, 59, 135)
hslhsl(233, 47%, 36%)
oklchoklch(0.389 0.126 273.4)
Closest name: Evening Magic (#363e7d)Relative luminance 0.0553

Colors that go with #313b87

Charcoal, Steel Blue and Blue 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 →

#877d31

#316687 · #523187

#87313b · #3b8731

Split-complementary

Open in tool →

#875231 · #668731

#873166 · #877d31 · #318752

Contrast

#313b87 as textRatioAAAA largeAAAFix
Aaon white
9.97:1passpasspassPasses AAA — no fix needed.
Aaon black
2.11:1failfailfail
  • AA: use #626dc6 as the text (4.52:1)
  • AAA: use #8b93d5 as the text (7.23:1)
  • AA: or shift the background to #b0b0b0 (4.6:1)
  • AAA: or shift the background to #d9d9d9 (7.06:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #313b87 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

#313b87 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #313b87
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 #313b87 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/313b87-9c9cc4-df884e-241f2d-e9eef1?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