Blueprint
Open in tool →Cyan and indigo on navy is the developer-tool look; amber is the only warm note, so it always reads as 'attention'.
Color
#51bffb
#51bffb
hex
#51bffbrgb
rgb(81, 191, 251)hsl
hsl(201, 96%, 65%)oklch
oklch(0.766 0.131 236.1)Closest name: Blue Mana (#68c2f5)Relative luminance 0.4598
Colors that go with #51bffb
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 #51bffb: softer than #000 and cool enough to feel like part of the same palette.
Dark Orange #ff8c00
complementaryshippedDark Orange sits directly opposite #51bffb 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 #51bffb in 4 real palettes, including Blueprint and Salesforce's brand system, as the accent.
Blue #0000ff
shipped4 real palettes, including Warp's brand system and Canva's brand system put Blue beside #51bffb, as the supporting colour.
Denim #1560bd
shippedDesigners have shipped Denim with #51bffb: 5 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 #51bffb: 4 real palettes, including Patreon's brand system and Figma's brand system, as the accent.
Midnight Blue #191970
shipped8 real palettes, including Kraken's brand system and Telehealth put Midnight Blue beside #51bffb, as the lead colour.
Periwinkle #ccccff
shippedPeriwinkle shows up next to #51bffb in 4 real palettes, including Mistral AI's brand system and Calendly's brand system, as the accent.
Real palettes that use #51bffb
Tints & shades
Harmonies
Contrast
| #51bffb as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 2.06:1 | fail | fail | fail | |
Aaon black | 10.2:1 | 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 #51bffb as the background.
Brands using this color
Palettes built around it
Fonts for this mood
#51bffb reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #51bffb
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 #51bffb and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/51bffb-9cb1c4-df4e62-1f222d-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