Frost & Ember
Open in tool →Navy and frost with one ember red — the classic cold-with-a-warm-accent structure, borrowed from a thousand ski posters.
Color
#21375f
#21375f
hex
#21375frgb
rgb(33, 55, 95)hsl
hsl(219, 48%, 25%)oklch
oklch(0.34 0.076 261.5)Closest name: Deep Sea Base (#2c2c57)Relative luminance 0.0388
Colors that go with #21375f
Dark Olive Green, Sea Green and Teal 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.
Dark Olive Green #556b2f
split-complementshippedDark Olive Green is a split-complement of #21375f: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #21375f — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Teal #008080
analogousshippedTeal is #21375f's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Sienna #a0522d
complementaryshippedSienna sits directly opposite #21375f on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Amber #ffbf00
shippedAmber is paired with #21375f in 4 real palettes, including Beach Hut and McDonald's's brand system, as the supporting colour.
Blue #0000ff
shipped13 real palettes, including Alaska Airlines's brand system and Jeep's brand system put Blue beside #21375f, as the accent.
Blush Pink #e8b4b8
shipped5 real palettes, including Rain Garden and Garden Wedding put Blush Pink beside #21375f, as the accent.
White Smoke #f5f5f5
neutralWhite Smoke is the surface for #21375f: a clean near-white with no warm cast, so the cool hue stays clear instead of drifting muddy.
Real palettes that use #21375f
Tints & shades
Harmonies
Contrast
| #21375f as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 11.82:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 1.78:1 | 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 #21375f as the background.
Brands using this color
Palettes built around it
Fonts for this mood
#21375f reads as cool, dark, luxury. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #21375f
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 #21375f and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/21375f-9ca5c4-df664e-211f2d-e9f0f1?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