Color

#304fb5

#304fb5
hex#304fb5
rgbrgb(48, 79, 181)
hslhsl(226, 58%, 45%)
oklchoklch(0.466 0.166 266.9)
Closest name: Blasphemous Blue (#3356aa)Relative luminance 0.0956

Colors that go with #304fb5

Charcoal, Sea Green and Steel 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 →

#b59630

#3092b5 · #5430b5

#b5304f · #4fb530

Split-complementary

Open in tool →

#b55430 · #92b530

#b53092 · #b59630 · #30b554

Contrast

#304fb5 as textRatioAAAA largeAAAFix
Aaon white
7.21:1passpasspassPasses AAA — no fix needed.
Aaon black
2.91:1failfailfail
  • AA: use #526fd1 as the text (4.55:1)
  • AAA: use #7e94dd as the text (7.17:1)
  • AA: or shift the background to #cfcfcf (4.63:1)
  • AAA: or shift the background to #fcfcfc (7.03:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #304fb5 as the background.

Brands using this color

Fonts for this mood

#304fb5 reads as cool, modern. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #304fb5
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 #304fb5 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/304fb5-9ca1c4-df774e-221f2d-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