Arcade
Open in tool →Hot pink, cyan and acid yellow on near-black — cabinet-glow neon; the black surface is what makes the colours light up.
Color
#51effb
#51effb
hex
#51effbrgb
rgb(81, 239, 251)hsl
hsl(184, 96%, 65%)oklch
oklch(0.876 0.13 202.4)Closest name: Aqua (#0ff0fe)Relative luminance 0.7045
Colors that go with #51effb
Charcoal, Deep Sky Blue and Light Coral 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 #51effb: softer than #000 and cool enough to feel like part of the same palette.
Deep Sky Blue #00bfff
analogousshippedDeep Sky Blue is #51effb's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Light Coral #f08080
complementaryshippedLight Coral sits directly opposite #51effb on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Taupe #483c32
shippedTaupe is paired with #51effb in 10 real palettes, including Boeing's brand system and Astro's brand system, as the text colour against it.
Dark Orange #ff8c00
split-complementshippedDark Orange is a split-complement of #51effb: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Crimson #dc143c
shippedCrimson is paired with #51effb in 3 real palettes, including Formula 1's brand system and Tiffany & Co.'s brand system, as the supporting colour.
Light Pink #ffb6c1
shippedLight Pink shows up next to #51effb in 3 real palettes, including Macaron and Pastel Pop, as the lead colour.
Midnight Blue #191970
shipped3 real palettes, including Blue Mono and First Snow put Midnight Blue beside #51effb, as the text colour against it.
Real palettes that use #51effb
Tints & shades
Harmonies
Contrast
| #51effb as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 1.39:1 | fail | fail | fail | |
Aaon black | 15.09:1 | pass | pass | pass | Passes AAA — no fix needed. |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #51effb 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
#51effb reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #51effb
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 #51effb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/51effb-a2b9be-df4e8a-1f262d-e9f1ee?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