Color

#21031d

#21031d
hex#21031d
rgbrgb(33, 3, 29)
hslhsl(308, 83%, 7%)
oklchoklch(0.177 0.067 333.6)
Closest name: Black Sabbath (#220022)Relative luminance 0.0048

Colors that go with #21031d

Blue Violet, Charcoal and Sea Green 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.

Real palettes that use #21031d

Tints & shades

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

Harmonies

Complementary

Open in tool →

#032107

#160321 · #21030e

#1d2103 · #031d21

Split-complementary

Open in tool →

#0e2103 · #032116

#211603 · #032107 · #030e21

Contrast

#21031d as textRatioAAAA largeAAAFix
Aaon white
19.17:1passpasspassPasses AAA — no fix needed.
Aaon black
1.1:1failfailfail
  • AA: use #d214b9 as the text (4.54:1)
  • AAA: use #ef57db as the text (7.06:1)
  • AA: or shift the background to #7d7d7d (4.66:1)
  • AAA: or shift the background to #9e9e9e (7.16:1)

Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #21031d 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

#21031d reads as warm, vivid, dark. The font library is tagged with the same vocabulary:

mcpConnect your agent — build around #21031d
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 #21031d and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link

tool url/palettes/new/21031d-c19fb8-87cb62-2d1f25-eee9f1?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