# #666c8f

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

## Values

- Hex: `#666c8f`
- RGB: rgb(102, 108, 143)
- HSL: hsl(231, 17%, 48%)
- OKLCH: oklch(0.54 0.055 276.8)
- Relative luminance: 0.1553
- Nearest named color: Dark Prince (#6b6c89, Δ 1.169) — https://brandsweets.com/colors/dark-prince
- Moods: cool, muted
- Page: https://brandsweets.com/colors/666c8f

## Tints & shades

- Tints (toward white): #73799c, #8287a6, #9195b1, #a0a4bb, #aeb2c6, #bdc0d0, #cccedb, #dbdde6, #eaebf0, #f9f9fb
- Shades (toward black): #5d6383, #535874, #4a4f68, #3f435a, #373a4e, #2f3142, #242633, #1c1d27, #111218, #08090c

## Harmonies

- Complementary: #8f8966
- Analogous: #66818f, #74668f
- Triadic: #8f666c, #6c8f66
- Split-complementary: #8f7466, #818f66
- Tetradic: #8f6681, #8f8966, #668f74

## Colors that go with #666c8f

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 #666c8f: 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
- **Sea Green** #2e8b57 [harmony, pool: triadic] — Sea Green completes a triad with #666c8f — 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), Lemon Squeezy (https://brandsweets.com/colors/brands/lemonsqueezy-com), Mushroom (https://brandsweets.com/palettes/neutral#mushroom), Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com). — https://brandsweets.com/colors/seagreen
- **Dark Olive Green** #556b2f [harmony, pool: complementary] — Dark Olive Green sits directly opposite #666c8f 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 #666c8f 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
- **Champagne** #f7e7ce [pool] — 6 real palettes, including Midnight Luxe and BrandSweets's brand system put Champagne beside #666c8f, as that palette's text colour. Seen in: Midnight Luxe (https://brandsweets.com/palettes/luxury#midnight-luxe), BrandSweets (https://brandsweets.com/colors/brands/brandsweets), Coffee Bar (https://brandsweets.com/palettes/dark#coffee-bar), Forest Floor (https://brandsweets.com/palettes/dark#forest-floor). — https://brandsweets.com/colors/champagne
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #666c8f: 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 #666c8f: 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 #666c8f 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), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com). — https://brandsweets.com/colors/crimson

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

- On white (#ffffff): 5.11:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #505571 (7.29:1)
- On black (#000000): 4.11:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #6d7397 (4.55:1); AA: background → #f2f2f2 (4.57:1); AAA: text → #9195b1 (7.14:1)

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/666c8f-9c9ec4-df834e-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: "#666c8f" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.