Color

#0a3d8a

#0a3d8a
hex#0a3d8a
rgbrgb(10, 61, 138)
hslhsl(216, 86%, 29%)
oklchoklch(0.379 0.139 259.6)
Closest name: Deep Space Royal (#223382)Relative luminance 0.0524

Colors that go with #0a3d8a

Charcoal, Crimson 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 →

#8a570a

#0a7d8a · #170a8a

#8a0a3d · #3d8a0a

Split-complementary

Open in tool →

#8a170a · #7d8a0a

#8a0a7d · #8a570a · #0a8a17

Contrast

#0a3d8a as textRatioAAAA largeAAAFix
Aaon white
10.26:1passpasspassPasses AAA — no fix needed.
Aaon black
2.05:1failfailfail
  • AA: use #1b70ee as the text (4.6:1)
  • AAA: use #5996f3 as the text (7.08:1)
  • AA: or shift the background to #adadad (4.57:1)
  • AAA: or shift the background to #d6d6d6 (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 #0a3d8a as the background.

Brands using this color

Palettes built around it

Fonts for this mood

#0a3d8a reads as cool, vivid, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #0a3d8a
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 #0a3d8a and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/0a3d8a-9ca7c4-df5f4e-201f2d-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