# #51b366

A color — neutral. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#51b366`
- RGB: rgb(81, 179, 102)
- HSL: hsl(133, 39%, 51%)
- OKLCH: oklch(0.689 0.145 148.4)
- Relative luminance: 0.3495
- Nearest named color: mediumseagreen (#3cb371, Δ 1.722) — https://brandsweets.com/colors/mediumseagreen
- Moods: neutral
- Page: https://brandsweets.com/colors/51b366

## Tints & shades

- Tints (toward white): #63bb76, #71c182, #83c992, #95d0a2, #a6d8b1, #b5debe, #c6e6cd, #d8eedd, #e6f4e9, #f8fcf9
- Shades (toward black): #48a35b, #419553, #3a8349, #327140, #2c6338, #24522e, #1c4024, #142e1a, #0e2012, #060e08

## Harmonies

- Complementary: #b3519e
- Analogous: #6db351, #51b397
- Triadic: #6651b3, #b36651
- Split-complementary: #9751b3, #b3516d
- Tetradic: #516db3, #b3519e, #b39751

## Colors that go with #51b366

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 body-text near-black for #51b366: its slight blue cast keeps type crisp beside a warm colour where pure #000 looks heavy. Seen in: Mint Modern (https://brandsweets.com/palettes/modern#mint-modern), Zendesk (https://brandsweets.com/colors/brands/zendesk-com), N26 (https://brandsweets.com/colors/brands/n26-com), Lagoon (https://brandsweets.com/palettes/vivid#lagoon). — https://brandsweets.com/colors/charcoal
- **Mustard Yellow** #ffdb58 [pool] — 4 real palettes, including Meadow and Citrus Grove put Mustard Yellow beside #51b366, as the supporting colour. Seen in: Meadow (https://brandsweets.com/palettes/light#meadow), Citrus Grove (https://brandsweets.com/palettes/warm#citrus-grove), Fresh Juice (https://brandsweets.com/palettes/playful#fresh-juice), Diner (https://brandsweets.com/palettes/vivid#diner). — https://brandsweets.com/colors/mustard
- **Royal Blue** #4169e1 [pool] — Royal Blue is paired with #51b366 in 5 real palettes, including Khan Academy's brand system and Console Light, as the accent. Seen in: Khan Academy (https://brandsweets.com/colors/brands/khanacademy-org), Console Light (https://brandsweets.com/palettes/technical#console-light), Telehealth (https://brandsweets.com/palettes/modern#telehealth), Brilliant (https://brandsweets.com/colors/brands/brilliant-org). — https://brandsweets.com/colors/royalblue
- **Taupe** #483c32 [pool] — Taupe is paired with #51b366 in 14 real palettes, including Undergrowth and Chime's brand system, as the surface under it. Seen in: Undergrowth (https://brandsweets.com/palettes/dark#undergrowth), Chime (https://brandsweets.com/colors/brands/chime-com), Meadow (https://brandsweets.com/palettes/light#meadow), Obsidian (https://brandsweets.com/colors/brands/obsidian-md). — https://brandsweets.com/colors/taupe
- **Orchid** #da70d6 [harmony: complementary] — Orchid sits directly opposite #51b366 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/orchid
- **Medium Purple** #9370db [harmony, pool: split] — Medium Purple is a split-complement of #51b366: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Obsidian (https://brandsweets.com/colors/brands/obsidian-md), Next.js (https://brandsweets.com/colors/brands/nextjs-org). — https://brandsweets.com/colors/mediumpurple
- **Blue** #0000ff [pool] — 3 real palettes, including Unity's brand system and Spotify's brand system put Blue beside #51b366, as the supporting colour. Seen in: Unity (https://brandsweets.com/colors/brands/unity-com), Spotify (https://brandsweets.com/colors/brands/spotify), Minecraft (https://brandsweets.com/colors/brands/minecraft-net). — https://brandsweets.com/colors/blue
- **Cornflower Blue** #6495ed [harmony, pool: triadic] — Cornflower Blue completes a triad with #51b366 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash. Seen in: Terminal (https://brandsweets.com/palettes/technical#terminal), Spotify (https://brandsweets.com/colors/brands/spotify). — https://brandsweets.com/colors/cornflowerblue

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

- On white (#ffffff): 2.63:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #3a8349 (4.64:1); AA: background → #363636 (4.6:1); AAA: text → #2c6338 (7.12:1); AAA: background → #141414 (7.01:1)
- On black (#000000): 7.99:1 — AA pass, AA-large pass, AAA pass

## Brands using this color

- **DuckDuckGo** — accent #38b26a (Δ 1.681) — https://brandsweets.com/colors/brands/duckduckgo-com

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/51b366-a2beab-b84edf-1f2d28-ebf1e9?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: "#51b366" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.