# #666b99

A color — cool, muted. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#666b99`
- RGB: rgb(102, 107, 153)
- HSL: hsl(234, 20%, 50%)
- OKLCH: oklch(0.542 0.072 278.9)
- Relative luminance: 0.1564
- Nearest named color: Bureaucracy (#746c8f, Δ 2.659) — https://brandsweets.com/colors/bureaucracy
- Moods: cool, muted
- Page: https://brandsweets.com/colors/666b99

## Tints & shades

- Tints (toward white): #757aa3, #8589ad, #9195b6, #a0a3c0, #afb2ca, #bfc1d4, #ced0de, #dadce7, #eaeaf1, #f9f9fb
- Shades (toward black): #5c608a, #54587d, #494d6e, #414562, #373a53, #2d2f43, #252737, #1b1c28, #12131c, #08090c

## Harmonies

- Complementary: #999466
- Analogous: #668599, #7a6699
- Triadic: #99666b, #6b9966
- Split-complementary: #997a66, #859966
- Tetradic: #996685, #999466, #66997a

## Colors that go with #666b99

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 #666b99: softer than #000 and cool enough to feel like part of the same palette. Seen in: Campus (https://brandsweets.com/palettes/friendly#campus), Plaid (https://brandsweets.com/colors/brands/plaid-com), Bloomberg (https://brandsweets.com/colors/brands/bloomberg-com), Hermès (https://brandsweets.com/colors/brands/hermes-com). — https://brandsweets.com/colors/charcoal
- **Dark Olive Green** #556b2f [harmony, pool: complementary] — Dark Olive Green sits directly opposite #666b99 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Magazine Ochre (https://brandsweets.com/palettes/editorial#magazine-ochre). — https://brandsweets.com/colors/darkolivegreen
- **Amber** #ffbf00 [pool] — Amber is paired with #666b99 in 6 real palettes, including Lemon Squeezy's brand system and Beach Hut, as the lead colour. Seen in: Lemon Squeezy (https://brandsweets.com/colors/brands/lemonsqueezy-com), Beach Hut (https://brandsweets.com/palettes/light#beach-hut), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com), Wired (https://brandsweets.com/colors/brands/wired-com). — https://brandsweets.com/colors/amber
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #666b99: 7 real palettes, including Fintech Trust and Ink & Paper, as the lead colour. Seen in: Fintech Trust (https://brandsweets.com/palettes/cool#fintech-trust), Ink & Paper (https://brandsweets.com/palettes/minimal#ink-and-paper), Glacier (https://brandsweets.com/palettes/cool#glacier), Hershey's (https://brandsweets.com/colors/brands/hersheys-com). — https://brandsweets.com/colors/cobalt
- **Copper** #b87333 [pool] — Designers have shipped Copper with #666b99: 4 real palettes, including Dusk and Riverbed, as the accent. Seen in: Dusk (https://brandsweets.com/palettes/cool#dusk), Riverbed (https://brandsweets.com/palettes/muted#riverbed), Atelier (https://brandsweets.com/palettes/elegant#atelier), Desert Road (https://brandsweets.com/palettes/warm#desert-road). — https://brandsweets.com/colors/copper
- **Crimson** #dc143c [pool] — Crimson is paired with #666b99 in 15 real palettes, including Retro Pop and Marvel's brand system, as the lead colour. Seen in: Retro Pop (https://brandsweets.com/palettes/playful#retro-pop), Marvel (https://brandsweets.com/colors/brands/marvel-com), Wendy's (https://brandsweets.com/colors/brands/wendys-com), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com). — https://brandsweets.com/colors/crimson
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #666b99: 5 real palettes, including Deep Water and Astro's brand system, as the lead colour. Seen in: Deep Water (https://brandsweets.com/palettes/dark#deep-water), Astro (https://brandsweets.com/colors/brands/astro-build), Venmo (https://brandsweets.com/colors/brands/venmo-com), Telegram (https://brandsweets.com/colors/brands/telegram-org). — https://brandsweets.com/colors/deepskyblue
- **Denim** #1560bd [pool] — Designers have shipped Denim with #666b99: 12 real palettes, including Campus and The New York Times's brand system, as the lead colour. Seen in: Campus (https://brandsweets.com/palettes/friendly#campus), The New York Times (https://brandsweets.com/colors/brands/nytimes-com), Discover (https://brandsweets.com/colors/brands/discover-com), American Express (https://brandsweets.com/colors/brands/americanexpress-com). — https://brandsweets.com/colors/denim

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

- On white (#ffffff): 5.09:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #52567a (7.07:1)
- On black (#000000): 4.13:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #6f749f (4.67:1); AA: background → #f2f2f2 (4.54:1); AAA: text → #9195b6 (7.18:1)

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/666b99-9d9cc4-df8a4e-241f2d-e9eef1?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: "#666b99" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.