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
#21eefd
#21eefd
hex
#21eefdrgb
rgb(33, 238, 253)hsl
hsl(184, 98%, 56%)oklch
oklch(0.866 0.144 203.2)Closest name: Aqua (#0ff0fe)Relative luminance 0.6856
Colors that go with #21eefd
Charcoal, Deep Sky Blue and Taupe 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 #21eefd: softer than #000 and cool enough to feel like part of the same palette.
Deep Sky Blue #00bfff
analogousshippedDeep Sky Blue is #21eefd's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Taupe #483c32
shippedTaupe is paired with #21eefd in 7 real palettes, including Boeing's brand system and Astro's brand system, as the text colour against it.
Salmon #fa8072
complementarySalmon sits directly opposite #21eefd on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Dark Orange #ff8c00
split-complementshippedDark Orange is a split-complement of #21eefd: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Crimson #dc143c
shippedCrimson is paired with #21eefd in 3 real palettes, including Formula 1's brand system and Frost & Ember, as the supporting colour.
Dodger Blue #1e90ff
shippedDesigners have shipped Dodger Blue with #21eefd: 3 real palettes, including Bluesky Social's brand system and Opensea's brand system, as the lead colour.
Light Pink #ffb6c1
shippedLight Pink shows up next to #21eefd in 3 real palettes, including Macaron and Pastel Pop, as the lead colour.
Real palettes that use #21eefd
Tints & shades
Harmonies
Contrast
| #21eefd as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 1.43:1 | fail | fail | fail | |
Aaon black | 14.71:1 | 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 #21eefd 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
#21eefd reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #21eefd
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 #21eefd and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/21eefd-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