Color
#21fdf9
#21fdf9rgb(33, 253, 249)hsl(179, 98%, 56%)oklch(0.9 0.151 192.7)Colors that go with #21fdf9
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 #21fdf9: softer than #000 and cool enough to feel like part of the same palette.
Deep Sky Blue #00bfff
analogousshippedDeep Sky Blue is #21fdf9'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 #21fdf9 in 5 real palettes, including Astro's brand system and Mint Chip, as the text colour against it.
Light Coral #f08080
complementaryLight Coral sits directly opposite #21fdf9 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Crimson #dc143c
shippedCrimson is paired with #21fdf9 in 3 real palettes, including Formula 1's brand system and Tiffany & Co.'s brand system, as the supporting colour.
Steel Blue #4682b4
shippedDesigners have shipped Steel Blue with #21fdf9: 3 real palettes, including Astro's brand system and Glacier, as the lead colour.
Coral #ff7f50
split-complementCoral is a split-complement of #21fdf9: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Hot Pink #ff69b4
split-complementHot Pink is a split-complement of #21fdf9: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Real palettes that use #21fdf9
Tints & shades
Harmonies
Contrast
| #21fdf9 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 1.27:1 | fail | fail | fail | |
Aaon black | 16.48:1 | 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 #21fdf9 as the background.
Brands using this color
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 #21fdf9 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/21fdf9-a2bbbe-d45996-1f272d-e9f1ed?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