Color
#181b3f
#181b3frgb(24, 27, 63)hsl(235, 45%, 17%)oklch(0.242 0.068 276.5)Colors that go with #181b3f
Charcoal, Dark Olive Green 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.
Charcoal #36454f
neutralshippedCharcoal is the text near-black for #181b3f: softer than #000 and cool enough to feel like part of the same palette.
Dark Olive Green #556b2f
complementaryshippedDark Olive Green sits directly opposite #181b3f on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #181b3f — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Sienna #a0522d
split-complementshippedSienna is a split-complement of #181b3f: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Slate Blue #6a5acd
analogousshippedSlate Blue is #181b3f's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Steel Blue #4682b4
analogousshippedSteel Blue is #181b3f's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Amber #ffbf00
shippedAmber is paired with #181b3f in 18 real palettes, including Southwest Airlines's brand system and Blueprint, as the accent.
Blue #0000ff
shipped21 real palettes, including Monzo's brand system and Sketch's brand system put Blue beside #181b3f, as the accent.
Real palettes that use #181b3f
Tints & shades
Harmonies
Contrast
| #181b3f as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 16.57:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 1.27:1 | 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 #181b3f as the background.
Brands using this color
Fonts for this mood
#181b3f reads as cool, dark, luxury. The font library is tagged with the same vocabulary:
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.
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
›analyze #181b3f and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/181b3f-9e9cc4-df8d4e-241f2d-e9eef1?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