# #666de5

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

## Values

- Hex: `#666de5`
- RGB: rgb(102, 109, 229)
- HSL: hsl(237, 71%, 65%)
- OKLCH: oklch(0.591 0.179 276.9)
- Relative luminance: 0.1942
- Nearest named color: Blue Öyster Cult (#5577ee, Δ 3.084) — https://brandsweets.com/colors/blue-oyster-cult
- Moods: cool, vivid, technical, modern
- Page: https://brandsweets.com/colors/666de5

## Tints & shades

- Tints (toward white): #7379e7, #858aea, #9297ed, #9fa3ef, #b1b4f2, #bec0f4, #cbcdf6, #d8d9f8, #e9eafb, #f6f7fe
- Shades (toward black): #4c54e1, #323bdc, #232bcd, #1e26b3, #1a2099, #151a7a, #101460, #0c0f46, #07092c, #030411

## Harmonies

- Complementary: #e5df66
- Analogous: #66ace5, #9f66e5
- Triadic: #e5666d, #6de566
- Split-complementary: #e59f66, #ace566
- Tetradic: #e566ac, #e5df66, #66e59f

## Colors that go with #666de5

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 #666de5: softer than #000 and cool enough to feel like part of the same palette. Seen in: Disney (https://brandsweets.com/colors/brands/disney-com), Docker (https://brandsweets.com/colors/brands/docker-com), Hinge (https://brandsweets.com/colors/brands/hinge-co), Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com). — https://brandsweets.com/colors/charcoal
- **Sea Green** #2e8b57 [harmony, pool: triadic] — Sea Green completes a triad with #666de5 — 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), Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com), Netflix (https://brandsweets.com/colors/brands/netflix). — https://brandsweets.com/colors/seagreen
- **Amber** #ffbf00 [pool] — Amber is paired with #666de5 in 9 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), Wikipedia (https://brandsweets.com/colors/brands/wikipedia-org), Walmart (https://brandsweets.com/colors/brands/walmart-com). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 13 real palettes, including Qualcomm's brand system and BBC's brand system put Blue beside #666de5, as the accent. Seen in: Qualcomm (https://brandsweets.com/colors/brands/qualcomm-com), BBC (https://brandsweets.com/colors/brands/bbc-com), Penpot (https://brandsweets.com/colors/brands/penpot-app), EA (https://brandsweets.com/colors/brands/ea-com). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #666de5: 10 real palettes, including Carrefour's brand system and Behance's brand system, as the accent. Seen in: Carrefour (https://brandsweets.com/colors/brands/carrefour-com), Behance (https://brandsweets.com/colors/brands/behance-net), Nokia (https://brandsweets.com/colors/brands/nokia-com), Intel (https://brandsweets.com/colors/brands/intel-com). — https://brandsweets.com/colors/cobalt
- **Cornflower Blue** #6495ed [pool] — Designers have shipped Cornflower Blue with #666de5: 5 real palettes, including Mastodon hosted on mastodon.social's brand system and Webflow's brand system, as the supporting colour. Seen in: Mastodon hosted on mastodon.social (https://brandsweets.com/colors/brands/mastodon-social), Webflow (https://brandsweets.com/colors/brands/webflow-com), Roblox (https://brandsweets.com/colors/brands/roblox-com), NBA (https://brandsweets.com/colors/brands/nba-com). — https://brandsweets.com/colors/cornflowerblue
- **Crimson** #dc143c [pool] — Crimson is paired with #666de5 in 12 real palettes, including Marvel's brand system and Pizza Hut's brand system, as the accent. Seen in: Marvel (https://brandsweets.com/colors/brands/marvel-com), Pizza Hut (https://brandsweets.com/colors/brands/pizzahut-com), Behance (https://brandsweets.com/colors/brands/behance-net), Foot Locker (https://brandsweets.com/colors/brands/footlocker-com). — https://brandsweets.com/colors/crimson
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #666de5: 9 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), Astro (https://brandsweets.com/colors/brands/astro-build), Patreon (https://brandsweets.com/colors/brands/patreon-com). — https://brandsweets.com/colors/deepskyblue

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

- On white (#ffffff): 4.3:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #6269e4 (4.51:1); AA: background → #0d0d0d (4.52:1); AAA: text → #363fdd (7.21:1)
- On black (#000000): 4.88:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #898eeb (7.13:1)

## 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/666de5-9f9cc4-df924e-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: "#666de5" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.