# #666f8a

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

## Values

- Hex: `#666f8a`
- RGB: rgb(102, 111, 138)
- HSL: hsl(225, 15%, 47%)
- OKLCH: oklch(0.544 0.044 270.5)
- Relative luminance: 0.1603
- Nearest named color: Dark Prince (#6b6c89, Δ 1.038) — https://brandsweets.com/colors/dark-prince
- Moods: cool, muted
- Page: https://brandsweets.com/colors/666f8a

## Tints & shades

- Tints (toward white): #727b97, #8189a2, #9097ad, #9ea5b7, #b0b5c4, #bec3cf, #cdd0da, #dcdee5, #eaecf0, #f9fafb
- Shades (toward black): #5d657e, #525a6f, #4a5064, #414758, #383d4c, #2e323e, #252832, #1c1f26, #111317, #09090c

## Harmonies

- Complementary: #8a8166
- Analogous: #66818a, #6f668a
- Triadic: #8a666f, #6f8a66
- Split-complementary: #8a6f66, #818a66
- Tetradic: #8a6681, #8a8166, #668a6f

## Colors that go with #666f8a

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 #666f8a: softer than #000 and cool enough to feel like part of the same palette. Seen in: Campus (https://brandsweets.com/palettes/friendly#campus), Bloomberg (https://brandsweets.com/colors/brands/bloomberg-com), Hermès (https://brandsweets.com/colors/brands/hermes-com), PlayStation® Official Site: Consoles, Games, Accessories & MoreSony Interactive Entertainment (https://brandsweets.com/colors/brands/playstation-com). — https://brandsweets.com/colors/charcoal
- **Sea Green** #2e8b57 [harmony, pool: triadic] — Sea Green completes a triad with #666f8a — 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), Mushroom (https://brandsweets.com/palettes/neutral#mushroom), Lemon Squeezy (https://brandsweets.com/colors/brands/lemonsqueezy-com), Intel (https://brandsweets.com/colors/brands/intel-com). — https://brandsweets.com/colors/seagreen
- **Dark Olive Green** #556b2f [harmony, pool: complementary] — Dark Olive Green sits directly opposite #666f8a 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 #666f8a in 5 real palettes, including Beach Hut and Lemon Squeezy's brand system, as the supporting colour. Seen in: Beach Hut (https://brandsweets.com/palettes/light#beach-hut), Lemon Squeezy (https://brandsweets.com/colors/brands/lemonsqueezy-com), Wired (https://brandsweets.com/colors/brands/wired-com), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com). — https://brandsweets.com/colors/amber
- **Champagne** #f7e7ce [pool] — 6 real palettes, including Midnight Luxe and Forest Floor put Champagne beside #666f8a, as that palette's text colour. Seen in: Midnight Luxe (https://brandsweets.com/palettes/luxury#midnight-luxe), Forest Floor (https://brandsweets.com/palettes/dark#forest-floor), Coffee Bar (https://brandsweets.com/palettes/dark#coffee-bar), BrandSweets (https://brandsweets.com/colors/brands/brandsweets). — https://brandsweets.com/colors/champagne
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #666f8a: 6 real palettes, including Ink & Paper and Fintech Trust, as the accent. Seen in: Ink & Paper (https://brandsweets.com/palettes/minimal#ink-and-paper), Fintech Trust (https://brandsweets.com/palettes/cool#fintech-trust), 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 #666f8a: 6 real palettes, including Riverbed and Dusk, as the accent. Seen in: Riverbed (https://brandsweets.com/palettes/muted#riverbed), Dusk (https://brandsweets.com/palettes/cool#dusk), 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 #666f8a in 10 real palettes, including Retro Pop and Wendy's's brand system, as the lead colour. Seen in: Retro Pop (https://brandsweets.com/palettes/playful#retro-pop), Wendy's (https://brandsweets.com/colors/brands/wendys-com), Marvel (https://brandsweets.com/colors/brands/marvel-com), Redfin (https://brandsweets.com/colors/brands/redfin-com). — https://brandsweets.com/colors/crimson

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

- On white (#ffffff): 4.99:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #50576d (7.18:1)
- On black (#000000): 4.21:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #6a7490 (4.51:1); AA: background → #f5f5f5 (4.58:1); AAA: text → #9097ad (7.22:1)

## Curated palettes containing it

- **Slate Workspace** (minimal, cool, clean, modern) — #0f172a, #64748b, #2563eb, #f8fafc — Slate on slate with a single blue — the productivity-app look where the interface disappears behind the work. — tool: https://brandsweets.com/palettes/new/0f172a-64748b-2563eb-f8fafc — collection: https://brandsweets.com/palettes/minimal
- **Clinic** (clean, cool, light) — #0e7490, #64748b, #f97316, #f8fafc, #0f172a — Teal reads clinical without the coldness of pure blue; the coral accent adds warmth for reassurance moments. — tool: https://brandsweets.com/palettes/new/0e7490-64748b-f97316-f8fafc-0f172a — collection: https://brandsweets.com/palettes/clean
- **Campus** (friendly, cool, clean) — #1d4ed8, #64748b, #f59e0b, #ffffff, #1e293b — Institutional blue with a highlighter-amber accent — trustworthy for parents, lively enough for students. — tool: https://brandsweets.com/palettes/new/1d4ed8-64748b-f59e0b-ffffff-1e293b — collection: https://brandsweets.com/palettes/friendly

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/666f8a-9ca1c4-df754e-221f2d-e9eff1?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: "#666f8a" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.