# #666b8a

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

## Values

- Hex: `#666b8a`
- RGB: rgb(102, 107, 138)
- HSL: hsl(232, 15%, 47%)
- OKLCH: oklch(0.535 0.049 277.5)
- Relative luminance: 0.1518
- Nearest named color: Dark Prince (#6b6c89, Δ 0.85) — https://brandsweets.com/colors/dark-prince
- Moods: cool, muted
- Page: https://brandsweets.com/colors/666b8a

## Tints & shades

- Tints (toward white): #727797, #8185a2, #9093ad, #9ea2b7, #b0b3c4, #bec1cf, #cdcfda, #dcdde5, #eaebf0, #f9f9fb
- Shades (toward black): #5d627e, #52566f, #4a4d64, #414458, #383b4c, #2e303e, #252732, #1c1e26, #111217, #09090c

## Harmonies

- Complementary: #8a8566
- Analogous: #667d8a, #73668a
- Triadic: #8a666b, #6b8a66
- Split-complementary: #8a7366, #7d8a66
- Tetradic: #8a667d, #8a8566, #668a73

## Colors that go with #666b8a

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 #666b8a: 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
- **Amber** #ffbf00 [pool] — Amber is paired with #666b8a in 5 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
- **Champagne** #f7e7ce [pool] — 6 real palettes, including BrandSweets's brand system and Coffee Bar put Champagne beside #666b8a. Seen in: BrandSweets (https://brandsweets.com/colors/brands/brandsweets), Coffee Bar (https://brandsweets.com/palettes/dark#coffee-bar), Midnight Luxe (https://brandsweets.com/palettes/luxury#midnight-luxe), Forest Floor (https://brandsweets.com/palettes/dark#forest-floor). — https://brandsweets.com/colors/champagne
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #666b8a: 6 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 #666b8a: 6 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), Desert Road (https://brandsweets.com/palettes/warm#desert-road), Atelier (https://brandsweets.com/palettes/elegant#atelier). — https://brandsweets.com/colors/copper
- **Crimson** #dc143c [pool] — Crimson is paired with #666b8a in 13 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), Redfin (https://brandsweets.com/colors/brands/redfin-com). — https://brandsweets.com/colors/crimson
- **Denim** #1560bd [pool] — Designers have shipped Denim with #666b8a: 10 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), HP (https://brandsweets.com/colors/brands/hp-com). — https://brandsweets.com/colors/denim
- **Dark Olive Green** #556b2f [harmony: complementary] — Dark Olive Green sits directly opposite #666b8a 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/darkolivegreen

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

- On white (#ffffff): 5.2:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #52566f (7.19:1)
- On black (#000000): 4.04:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #6f7495 (4.61:1); AA: background → #f0f0f0 (4.57:1); AAA: text → #9296af (7.2:1)

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/666b8a-9c9dc4-df864e-231f2d-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: "#666b8a" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.