Color

#399def

#399def
hex#399def
rgbrgb(57, 157, 239)
hslhsl(207, 85%, 58%)
oklchoklch(0.677 0.152 247.5)
Closest name: Fresh Blue of Bel Air (#069af3)Relative luminance 0.3122

Tints & shades

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

Harmonies

Complementary

Open in tool →

#ef8b39

#39efe6 · #3942ef

#ef399d · #9def39

Split-complementary

Open in tool →

#ef3942 · #efe639

#e639ef · #ef8b39 · #42ef39

Contrast

#399def as textRatioAAAA largeAAAFix
Aaon white
2.9:1failfailfail
  • AA: use #1077cb as the text (4.64:1)
  • AAA: use #0d5b9c as the text (7.01:1)
  • AA: or shift the background to #303030 (4.55:1)
  • AAA: or shift the background to #050505 (7.03:1)
Aaon black
7.24:1passpasspassPasses AAA — no fix needed.

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #399def 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

#399def reads as cool, vivid, technical. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #399def
live endpoint

Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — generate_palette, check_contrast, analyze_color — read-only, no key. Every palette it proposes comes with a /palettes/new/… link: open it, lock what you like, paste the link back.

endpointhttps://mcp.brandsweets.com/colors/mcp
claude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt

analyze #399def and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/399def-9cadc4-df4e53-1f212d-e9f1f1?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