Learning App
Open in tool →Green, blue and orange at full saturation: the gamified-learning look, where every color is a reward.
Color
#21b3f2
#21b3f2
hex
#21b3f2rgb
rgb(33, 179, 242)hsl
hsl(198, 89%, 54%)oklch
oklch(0.724 0.145 234.1)Closest name: Blue Bikini (#00bbee)Relative luminance 0.3897
Colors that go with #21b3f2
Charcoal, Dark Orange and Amber 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 #21b3f2: softer than #000 and cool enough to feel like part of the same palette.
Dark Orange #ff8c00
complementaryshippedDark Orange sits directly opposite #21b3f2 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Amber #ffbf00
shippedAmber is paired with #21b3f2 in 5 real palettes, including Salesforce's brand system and Blueprint, as the accent.
Blue #0000ff
shipped4 real palettes, including Warp's brand system and Canva's brand system put Blue beside #21b3f2, as the supporting colour.
Denim #1560bd
shippedDesigners have shipped Denim with #21b3f2: 6 real palettes, including Venmo's brand system and Coca-Cola's brand system, as the accent.
Dodger Blue #1e90ff
shippedDesigners have shipped Dodger Blue with #21b3f2: 4 real palettes, including Figma's brand system and Venmo's brand system, as the accent.
Medium Sea Green #3cb371
shippedMedium Sea Green is paired with #21b3f2 in 4 real palettes, including Terminal and Unity's brand system, as the lead colour.
Midnight Blue #191970
shipped8 real palettes, including Kraken's brand system and Blue Mono put Midnight Blue beside #21b3f2, as the lead colour.
Real palettes that use #21b3f2
Tints & shades
Harmonies
Contrast
| #21b3f2 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 2.39:1 | fail | fail | fail | |
Aaon black | 8.79:1 | 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 #21b3f2 as the background.
Brands using this color
Palettes built around it
Fonts for this mood
#21b3f2 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #21b3f2
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 #21b3f2 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/21b3f2-9cb3c4-df4e69-1f232d-e9f1f0?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