Heatwave
Open in tool →Blaze orange and hot yellow with one cold blue — the high-noon palette; use the blue where the eye needs to rest.
Color
#210f03
#210f03
hex
#210f03rgb
rgb(33, 15, 3)hsl
hsl(24, 83%, 7%)oklch
oklch(0.192 0.039 56.2)Closest name: Soulless (#1b150d)Relative luminance 0.0067
Colors that go with #210f03
Blue Violet, Charcoal and Royal 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.
Blue Violet #8a2be2
triadicshippedBlue Violet completes a triad with #210f03 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Charcoal #36454f
neutralshippedCharcoal is the body-text near-black for #210f03: its slight blue cast keeps type crisp beside a warm colour where pure #000 looks heavy.
Royal Blue #4169e1
split-complementshippedRoyal Blue is a split-complement of #210f03: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Rust #b7410e
analogousshippedRust is #210f03's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Steel Blue #4682b4
complementaryshippedSteel Blue sits directly opposite #210f03 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Teal #008080
split-complementshippedTeal is a split-complement of #210f03: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Amber #ffbf00
shippedAmber is paired with #210f03 in 18 real palettes, including Heatwave and Ember, as the supporting colour.
Blue #0000ff
shipped22 real palettes, including Robinhood's brand system and native Cybersecurity's brand system put Blue beside #210f03, as the supporting colour.
Real palettes that use #210f03
Tints & shades
Harmonies
Contrast
| #210f03 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 18.51:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 1.13:1 | fail | fail | fail |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #210f03 as the background.
Brands using this color
No public brand in the corpus uses this exact color yet. Extract a brand to add one.
Palettes built around it
Fonts for this mood
#210f03 reads as warm, vivid, dark. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #210f03
live endpointPoint 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.
endpoint
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt
›analyze #210f03 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/210f03-c4b19c-62cbc2-2d2b1f-f1e9ea?lock=0&style=vibrantWant the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.
Machine-readable: color.md