# #666bf9

A color — cool, vivid, technical, modern. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#666bf9`
- RGB: rgb(102, 107, 249)
- HSL: hsl(238, 92%, 69%)
- OKLCH: oklch(0.602 0.208 276.7)
- Relative luminance: 0.2018
- Nearest named color: mediumslateblue (#7b68ee, Δ 3.392) — https://brandsweets.com/colors/mediumslateblue
- Moods: cool, vivid, technical, modern
- Page: https://brandsweets.com/colors/666bf9

## Tints & shades

- Tints (toward white): #767af9, #8589fa, #9397fb, #a2a5fb, #b1b3fc, #babdfc, #c9cbfd, #d8d9fd, #e7e7fe, #f5f6ff
- Shades (toward black): #4a50f7, #282ef6, #0a12f5, #090fd3, #080db5, #060b93, #050976, #030653, #020436, #010114

## Harmonies

- Complementary: #f9f467
- Analogous: #67b5f9, #ab67f9
- Triadic: #f9676c, #6cf967
- Split-complementary: #f9ab67, #b5f967
- Tetradic: #f967b5, #f9f467, #67f9ab

## Colors that go with #666bf9

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 text near-black for #666bf9: softer than #000 and cool enough to feel like part of the same palette. Seen in: Docker (https://brandsweets.com/colors/brands/docker-com), Zoom (https://brandsweets.com/colors/brands/zoom-us), Disney (https://brandsweets.com/colors/brands/disney-com), Hinge (https://brandsweets.com/colors/brands/hinge-co). — https://brandsweets.com/colors/charcoal
- **Sea Green** #2e8b57 [harmony, pool: triadic] — Sea Green completes a triad with #666bf9 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash. Seen in: Subaru (https://brandsweets.com/colors/brands/subaru-com), Next.js (https://brandsweets.com/colors/brands/nextjs-org), Coinbase (https://brandsweets.com/colors/brands/coinbase), Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com). — https://brandsweets.com/colors/seagreen
- **Amber** #ffbf00 [pool] — Amber is paired with #666bf9 in 8 real palettes, including Mastodon hosted on mastodon.social's brand system and Google's brand system, as the accent. Seen in: Mastodon hosted on mastodon.social (https://brandsweets.com/colors/brands/mastodon-social), Google (https://brandsweets.com/colors/brands/google-com), Walmart (https://brandsweets.com/colors/brands/walmart-com), Blueprint (https://brandsweets.com/palettes/technical#blueprint). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 13 real palettes, including Signal's brand system and Penpot's brand system put Blue beside #666bf9, as the supporting colour. Seen in: Signal (https://brandsweets.com/colors/brands/signal-org), Penpot (https://brandsweets.com/colors/brands/penpot-app), Qualcomm (https://brandsweets.com/colors/brands/qualcomm-com), Cargo (https://brandsweets.com/colors/brands/cargo-site). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #666bf9: 8 real palettes, including Behance's brand system and Carrefour's brand system, as the supporting colour. Seen in: Behance (https://brandsweets.com/colors/brands/behance-net), Carrefour (https://brandsweets.com/colors/brands/carrefour-com), Nivea (https://brandsweets.com/colors/brands/nivea-com), Nokia (https://brandsweets.com/colors/brands/nokia-com). — https://brandsweets.com/colors/cobalt
- **Cornflower Blue** #6495ed [pool] — Designers have shipped Cornflower Blue with #666bf9: 5 real palettes, including Mastodon hosted on mastodon.social's brand system and Roblox's brand system, as the supporting colour. Seen in: Mastodon hosted on mastodon.social (https://brandsweets.com/colors/brands/mastodon-social), Roblox (https://brandsweets.com/colors/brands/roblox-com), Webflow (https://brandsweets.com/colors/brands/webflow-com), NBA (https://brandsweets.com/colors/brands/nba-com). — https://brandsweets.com/colors/cornflowerblue
- **Crimson** #dc143c [pool] — Crimson is paired with #666bf9 in 10 real palettes, including Behance's brand system and WWE's brand system, as the accent. Seen in: Behance (https://brandsweets.com/colors/brands/behance-net), WWE (https://brandsweets.com/colors/brands/wwe-com), Toyota (https://brandsweets.com/colors/brands/toyota-com), Chase (https://brandsweets.com/colors/brands/chase-com). — https://brandsweets.com/colors/crimson
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #666bf9: 7 real palettes, including Calm's brand system and Elastic's brand system, as the lead colour. Seen in: Calm (https://brandsweets.com/colors/brands/calm-com), Elastic (https://brandsweets.com/colors/brands/elastic-co), Patreon (https://brandsweets.com/colors/brands/patreon-com), Venmo (https://brandsweets.com/colors/brands/venmo-com). — https://brandsweets.com/colors/deepskyblue

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

- On white (#ffffff): 4.17:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #5d63f8 (4.56:1); AA: background → #0f0f0f (4.6:1); AAA: text → #2c33f6 (7.21:1)
- On black (#000000): 5.04:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #898dfa (7.25:1)

## Brands using this color

- **Mastodon hosted on mastodon.social** — primary #6464fc (Δ 1.691) — https://brandsweets.com/colors/brands/mastodon-social

## Fonts for this mood

- technical: https://brandsweets.com/fonts/mood/technical
- modern: https://brandsweets.com/fonts/mood/modern

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/666bf9-9f9cc4-df944e-251f2d-e9edf1?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: "#666bf9" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.