Color

#303b50

#303b50
hex#303b50
rgbrgb(48, 59, 80)
hslhsl(219, 25%, 25%)
oklchoklch(0.352 0.04 263)
Closest name: Capital Blue (#1a4157)Relative luminance 0.0434

Colors that go with #303b50

Dark Olive Green, 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 →

#504530

#304b50 · #353050

#50303b · #3b5030

Split-complementary

Open in tool →

#503530 · #4b5030

#50304b · #504530 · #305035

Contrast

#303b50 as textRatioAAAA largeAAAFix
Aaon white
11.25:1passpasspassPasses AAA — no fix needed.
Aaon black
1.87:1failfailfail
  • AA: use #60769f as the text (4.59:1)
  • AAA: use #8697b6 as the text (7.12:1)
  • AA: or shift the background to #a6a6a6 (4.62:1)
  • AAA: or shift the background to #cccccc (7:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #303b50 as the background.

Brands using this color

Fonts for this mood

#303b50 reads as cool, muted, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #303b50
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 #303b50 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/303b50-9ca5c4-df664e-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