Blue Mono
Open in tool →One blue at four lightnesses — monochromatic in the colour-theory sense; the deep step is the text, the pale step the surface tint.
Color
#669ff0
#669ff0
hex
#669ff0rgb
rgb(102, 159, 240)hsl
hsl(215, 82%, 67%)oklch
oklch(0.698 0.134 257.3)Closest name: cornflowerblue (#6495ed)Relative luminance 0.3391
Colors that go with #669ff0
Charcoal, Medium Sea Green and Peru 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 #669ff0: softer than #000 and cool enough to feel like part of the same palette.
Medium Sea Green #3cb371
triadicshippedMedium Sea Green completes a triad with #669ff0 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Peru #cd853f
complementaryshippedPeru sits directly opposite #669ff0 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 #669ff0 in 7 real palettes, including NBA's brand system and Ahrefs's brand system, as the lead colour.
Blue #0000ff
shipped6 real palettes, including Canva's brand system and Spotify's brand system put Blue beside #669ff0, as the accent.
Dark Orange #ff8c00
shippedDark Orange shows up next to #669ff0 in 5 real palettes, including Ahrefs's brand system and Learning App, as the lead colour.
Denim #1560bd
shippedDesigners have shipped Denim with #669ff0: 7 real palettes, including Coca-Cola's brand system and Venmo's brand system, as the accent.
Emerald Green #50c878
shippedEmerald Green is paired with #669ff0 in 4 real palettes, including Playground and Obsidian's brand system, as the accent.
Real palettes that use #669ff0
Tints & shades
Harmonies
Contrast
| #669ff0 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 2.7:1 | fail | fail | fail | |
Aaon black | 7.78:1 | 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 #669ff0 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
#669ff0 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #669ff0
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 #669ff0 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/669ff0-9ca8c4-df5d4e-201f2d-e9f0f1?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