Color

#537be9

#537be9
hex#537be9
rgbrgb(83, 123, 233)
hslhsl(224, 77%, 62%)
oklchoklch(0.61 0.172 266.4)
Closest name: Blue Öyster Cult (#5577ee)Relative luminance 0.2189

Colors that go with #537be9

Charcoal, Crimson and Copper 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 →

#e9c153

#53c6e9 · #7653e9

#e9537b · #7be953

Split-complementary

Open in tool →

#e97653 · #c6e953

#e953c6 · #e9c153 · #53e976

Contrast

#537be9 as textRatioAAAA largeAAAFix
Aaon white
3.91:1failpassfail
  • AA: use #416de6 as the text (4.61:1)
  • AAA: use #1b4bd0 as the text (7.09:1)
  • AA: or shift the background to #171717 (4.59:1)
Aaon black
5.38:1passpassfail
  • AAA: use #7394ed as the text (7.19:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #537be9 as the background.

Brands using this color

Fonts for this mood

#537be9 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #537be9
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 #537be9 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/537be9-9ca2c4-df724e-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