# #3f5378

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

## Values

- Hex: `#3f5378`
- RGB: rgb(63, 83, 120)
- HSL: hsl(219, 31%, 36%)
- OKLCH: oklch(0.442 0.066 262.2)
- Relative luminance: 0.086
- Nearest named color: Deep Indigo (#4c567a, Δ 2.141) — https://brandsweets.com/colors/deep-indigo
- Moods: cool, muted
- Page: https://brandsweets.com/colors/3f5378

## Tints & shades

- Tints (toward white): #4a618c, #546fa0, #6982b0, #7d92ba, #91a3c5, #a5b4cf, #b9c4da, #d0d8e6, #e4e9f1, #f8f9fb
- Shades (toward black): #3a4c6e, #354564, #2e3c57, #28354d, #232e43, #1e2739, #19202f, #121721, #0c1017, #07090d

## Harmonies

- Complementary: #78643f
- Analogous: #3f7078, #483f78
- Triadic: #783f53, #53783f
- Split-complementary: #78483f, #70783f
- Tetradic: #783f70, #78643f, #3f7848

## Colors that go with #3f5378

Named partners (harmony on the OKLCH wheel, co-occurrence in curated palettes and brand systems, and the neutrals that carry it), best first:

- **Sea Green** #2e8b57 [harmony, pool: triadic] — Sea Green completes a triad with #3f5378 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash. Seen in: Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com), Subaru (https://brandsweets.com/colors/brands/subaru-com), Netflix (https://brandsweets.com/colors/brands/netflix), Paramount+ (https://brandsweets.com/colors/brands/paramountplus-com). — https://brandsweets.com/colors/seagreen
- **Teal** #008080 [harmony, pool: analogous] — Teal is #3f5378's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Stanley (https://brandsweets.com/colors/brands/stanley1913-com), Gusto (https://brandsweets.com/colors/brands/gusto-com), Sapphire & Gold (https://brandsweets.com/palettes/luxury#sapphire-and-gold), Magazine Ochre (https://brandsweets.com/palettes/editorial#magazine-ochre). — https://brandsweets.com/colors/teal
- **Sienna** #a0522d [harmony, pool: complementary] — Sienna sits directly opposite #3f5378 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: BrandSweets (https://brandsweets.com/colors/brands/brandsweets). — https://brandsweets.com/colors/sienna
- **Blue** #0000ff [pool] — 7 real palettes, including Tesco's brand system and CVS's brand system put Blue beside #3f5378, as the supporting colour. Seen in: Tesco (https://brandsweets.com/colors/brands/tesco-com), CVS (https://brandsweets.com/colors/brands/cvs-com), Alaska Airlines (https://brandsweets.com/colors/brands/alaskaair-com), Activision (https://brandsweets.com/colors/brands/activision-com). — https://brandsweets.com/colors/blue
- **Cadet Blue** #5f9ea0 [pool] — Designers have shipped Cadet Blue with #3f5378: 4 real palettes, including Dusk and Open House, as the supporting colour. Seen in: Dusk (https://brandsweets.com/palettes/cool#dusk), Open House (https://brandsweets.com/palettes/clean#open-house), Alpine (https://brandsweets.com/palettes/cool#alpine), Paper & Pine (https://brandsweets.com/palettes/minimal#paper-and-pine). — https://brandsweets.com/colors/cadetblue
- **Crimson** #dc143c [pool] — Crimson is paired with #3f5378 in 14 real palettes, including Codecademy's brand system and Walgreens's brand system, as the accent. Seen in: Codecademy (https://brandsweets.com/colors/brands/codecademy-com), Walgreens (https://brandsweets.com/colors/brands/walgreens-com), Wells Fargo (https://brandsweets.com/colors/brands/wellsfargo-com), Costco (https://brandsweets.com/colors/brands/costco-com). — https://brandsweets.com/colors/crimson
- **Denim** #1560bd [pool] — Designers have shipped Denim with #3f5378: 17 real palettes, including HP's brand system and Dutch Bros's brand system, as the accent. Seen in: HP (https://brandsweets.com/colors/brands/hp-com), Dutch Bros (https://brandsweets.com/colors/brands/dutchbros-com), The New York Times (https://brandsweets.com/colors/brands/nytimes-com), Hinge (https://brandsweets.com/colors/brands/hinge-co). — https://brandsweets.com/colors/denim
- **White Smoke** #f5f5f5 [role] — White Smoke is the surface for #3f5378: a clean near-white with no warm cast, so the cool hue stays clear instead of drifting muddy. — https://brandsweets.com/colors/whitesmoke

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

- On white (#ffffff): 7.72:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 2.72:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #5b76a9 (4.61:1); AA: background → #c7c7c7 (4.57:1); AAA: text → #8398be (7.2:1); AAA: background → #f5f5f5 (7.08:1)

## Brands using this color

- **HP** — secondary #485571 (Δ 1.91) — https://brandsweets.com/colors/brands/hp-com

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/3f5378-9ca5c4-df664e-211f2d-e9f0f1?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: "#3f5378" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.