# #21d9ed

A color — cool, vivid, technical, modern. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#21d9ed`
- RGB: rgb(33, 217, 237)
- HSL: hsl(186, 85%, 53%)
- OKLCH: oklch(0.811 0.135 207)
- Relative luminance: 0.5606
- Nearest named color: mediumturquoise (#48d1cc, Δ 4.527) — https://brandsweets.com/colors/mediumturquoise
- Moods: cool, vivid, technical, modern
- Page: https://brandsweets.com/colors/21d9ed

## Tints & shades

- Tints (toward white): #39ddef, #4ce0f0, #63e4f2, #76e7f4, #8eebf6, #a1eff7, #b8f3f9, #cbf6fb, #e3fafd, #f6fdfe
- Shades (toward black): #12cee2, #10b8cb, #0fa3b3, #0d8d9c, #0b7c89, #096771, #07515a, #053c42, #03272a, #021113

## Harmonies

- Complementary: #ed3621
- Analogous: #21ed9c, #2173ed
- Triadic: #ed21d9, #d9ed21
- Split-complementary: #ed2173, #ed9c21
- Tetradic: #9c21ed, #ed3621, #73ed21

## Colors that go with #21d9ed

Named partners (harmony on the OKLCH wheel, co-occurrence in curated palettes and brand systems, and the neutrals that carry it), best first:

- **Charcoal** #36454f [role, pool] — Charcoal is the text near-black for #21d9ed: softer than #000 and cool enough to feel like part of the same palette. Seen in: UEFA (https://brandsweets.com/colors/brands/uefa-com), Vimeo (https://brandsweets.com/colors/brands/vimeo-com), Boeing (https://brandsweets.com/colors/brands/boeing-com), Coastal (https://brandsweets.com/palettes/cool#coastal). — https://brandsweets.com/colors/charcoal
- **Crimson** #dc143c [pool] — Crimson is paired with #21d9ed in 4 real palettes, including Riot Games's brand system and Tiffany & Co.'s brand system, as the supporting colour. Seen in: Riot Games (https://brandsweets.com/colors/brands/riotgames-com), Tiffany & Co. (https://brandsweets.com/colors/brands/tiffany-com), Frost & Ember (https://brandsweets.com/palettes/bold#frost-and-ember), Formula 1 (https://brandsweets.com/colors/brands/formula1-com). — https://brandsweets.com/colors/crimson
- **Dodger Blue** #1e90ff [pool] — Designers have shipped Dodger Blue with #21d9ed: 5 real palettes, including Patreon's brand system and Opensea's brand system, as the accent. Seen in: Patreon (https://brandsweets.com/colors/brands/patreon-com), Opensea (https://brandsweets.com/colors/brands/opensea-io), Figma (https://brandsweets.com/colors/brands/figma), Bluesky Social (https://brandsweets.com/colors/brands/bsky-app). — https://brandsweets.com/colors/dodgerblue
- **Taupe** #483c32 [pool] — Taupe is paired with #21d9ed in 9 real palettes, including Crayon Box and Boeing's brand system, as the text colour against it. Seen in: Crayon Box (https://brandsweets.com/palettes/playful#crayon-box), Boeing (https://brandsweets.com/colors/brands/boeing-com), Mint Chip (https://brandsweets.com/palettes/light#mint-chip), Macaron (https://brandsweets.com/palettes/light#macaron). — https://brandsweets.com/colors/taupe
- **Salmon** #fa8072 [harmony: complementary] — Salmon sits directly opposite #21d9ed on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. — https://brandsweets.com/colors/salmon
- **Dark Orange** #ff8c00 [harmony, pool: split] — Dark Orange is a split-complement of #21d9ed: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: PayPal (https://brandsweets.com/colors/brands/paypal-com), Learning App (https://brandsweets.com/palettes/playful#learning-app). — https://brandsweets.com/colors/darkorange
- **Blue** #0000ff [pool] — 3 real palettes, including Canva's brand system and Warp's brand system put Blue beside #21d9ed, as the accent. Seen in: Canva (https://brandsweets.com/colors/brands/canva-com), Warp (https://brandsweets.com/colors/brands/warp-dev), Uber (https://brandsweets.com/colors/brands/uber-com). — https://brandsweets.com/colors/blue
- **Khaki** #f0e68c [pool] — 3 real palettes, including Pastel Pop and Nursery put Khaki beside #21d9ed, as the accent. Seen in: Pastel Pop (https://brandsweets.com/palettes/playful#pastel-pop), Nursery (https://brandsweets.com/palettes/light#nursery), Lagoon (https://brandsweets.com/palettes/vivid#lagoon). — https://brandsweets.com/colors/khaki

## Contrast (WCAG 2.x, as text)

- On white (#ffffff): 1.72:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #0b818e (4.62:1); AA: background → #525252 (4.54:1); AAA: text → #085e68 (7.47:1); AAA: background → #363636 (7.03:1)
- On black (#000000): 12.21:1 — AA pass, AA-large pass, AAA pass

## Brands using this color

- **UEFA** — primary #00d9f7 (Δ 1.458) — https://brandsweets.com/colors/brands/uefa-com
- **Prisma** — accent #01d7e4 (Δ 1.463) — https://brandsweets.com/colors/brands/prisma-io

## Fonts for this mood

- technical: https://brandsweets.com/fonts/mood/technical
- modern: https://brandsweets.com/fonts/mood/modern

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/21d9ed-a2b8be-df4e86-1f262d-e9f1ee?lock=0&style=vibrant
(Humans lock/regenerate in the tool; the URL is the state — read `lock=` back to see what they kept.)

## Connect an agent

Point any MCP client at the BrandSweets colors endpoint for the same engine:

- Endpoint: https://mcp.brandsweets.com/colors/mcp
- Tools: `analyze_color` (e.g. `analyze_color({ color: "#21d9ed" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.