Learning App
Open in tool →Green, blue and orange at full saturation: the gamified-learning look, where every color is a reward.
Color
#66cb01
#66cb01
hex
#66cb01rgb
rgb(102, 203, 1)hsl
hsl(90, 99%, 40%)oklch
oklch(0.751 0.222 135.7)Closest name: Blinking Terminal (#66cc00)Relative luminance 0.4554
Colors that go with #66cb01
Blue, Taupe and Violet 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.
Blue #0000ff
shipped4 real palettes, including Minecraft's brand system and Spotify's brand system put Blue beside #66cb01, as the accent.
Taupe #483c32
shippedTaupe is paired with #66cb01 in 9 real palettes, including Minecraft's brand system and Acer's brand system, as the lead colour.
Violet #ee82ee
complementaryViolet sits directly opposite #66cb01 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Hot Pink #ff69b4
split-complementshippedHot Pink is a split-complement of #66cb01: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Charcoal #36454f
neutralshippedCharcoal is the body-text near-black for #66cb01: its slight blue cast keeps type crisp beside a warm colour where pure #000 looks heavy.
Dark Orange #ff8c00
shippedDark Orange shows up next to #66cb01 in 3 real palettes, including Learning App and Citrus Grove, as the accent.
Deep Sky Blue #00bfff
triadicshippedDeep Sky Blue completes a triad with #66cb01 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Royal Blue #4169e1
shippedRoyal Blue is paired with #66cb01 in 3 real palettes, including Brilliant's brand system and MongoDB's brand system, as the accent.
Real palettes that use #66cb01
Tints & shades
Harmonies
Contrast
| #66cb01 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 2.08:1 | fail | fail | fail | |
Aaon black | 10.11:1 | 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 #66cb01 as the background.
Brands using this color
Palettes built around it
mcpConnect your agent — build around #66cb01
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 #66cb01 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/66cb01-adbea2-514edf-202d1f-f1f1e9?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