# #331b9d

A color — cool, vivid, technical, modern. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#331b9d`
- RGB: rgb(51, 27, 157)
- HSL: hsl(251, 71%, 36%)
- OKLCH: oklch(0.361 0.191 279.3)
- Relative luminance: 0.0392
- Nearest named color: Depths of Night (#2c319b, Δ 3.793) — https://brandsweets.com/colors/depths-of-night
- Moods: cool, vivid, technical, modern
- Page: https://brandsweets.com/colors/331b9d

## Tints & shades

- Tints (toward white): #3b1fb7, #4323d1, #593bde, #6f55e2, #856fe7, #9b89eb, #b1a3ef, #cbc2f5, #e1dcf9, #f8f6fe
- Shades (toward black): #2e1890, #2a1683, #241371, #201164, #1c0f57, #180d4a, #140a3d, #0e072c, #0a051f, #060311

## Harmonies

- Complementary: #859d1b
- Analogous: #1b449d, #741b9d
- Triadic: #9d331b, #1b9d33
- Split-complementary: #9d741b, #449d1b
- Tetradic: #9d1b44, #859d1b, #1b9d74

## Colors that go with #331b9d

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

- **Steel Blue** #4682b4 [harmony, pool: analogous] — Steel Blue is #331b9d's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: FedEx (https://brandsweets.com/colors/brands/fedex-com), Hershey's (https://brandsweets.com/colors/brands/hersheys-com), Fintech Trust (https://brandsweets.com/palettes/cool#fintech-trust), Glacier (https://brandsweets.com/palettes/cool#glacier). — https://brandsweets.com/colors/steelblue
- **Blue** #0000ff [pool] — 4 real palettes, including Procter & Gamble's brand system and Pfizer's brand system put Blue beside #331b9d, as the supporting colour. Seen in: Procter & Gamble (https://brandsweets.com/colors/brands/pg-com), Pfizer (https://brandsweets.com/colors/brands/pfizer-com), Zillow (https://brandsweets.com/colors/brands/zillow-com), CVS (https://brandsweets.com/colors/brands/cvs-com). — https://brandsweets.com/colors/blue
- **Crimson** #dc143c [pool] — Crimson is paired with #331b9d in 7 real palettes, including Pepsi's brand system and Casper Sleep's brand system, as the supporting colour. Seen in: Pepsi (https://brandsweets.com/colors/brands/pepsi-com), Casper Sleep (https://brandsweets.com/colors/brands/casper-com), Nintendo (https://brandsweets.com/colors/brands/nintendo-com), Walgreens (https://brandsweets.com/colors/brands/walgreens-com). — https://brandsweets.com/colors/crimson
- **Denim** #1560bd [pool] — Designers have shipped Denim with #331b9d: 4 real palettes, including Warbyparker's brand system and Unilever's brand system, as the accent. Seen in: Warbyparker (https://brandsweets.com/colors/brands/warbyparker-com), Unilever (https://brandsweets.com/colors/brands/unilever-com), Bank of America (https://brandsweets.com/colors/brands/bankofamerica-com), Intel (https://brandsweets.com/colors/brands/intel-com). — https://brandsweets.com/colors/denim
- **Firebrick** #b22222 [pool] — Designers have shipped Firebrick with #331b9d: 4 real palettes, including 3M's brand system and Nintendo's brand system, as the supporting colour. Seen in: 3M (https://brandsweets.com/colors/brands/3m-com), Nintendo (https://brandsweets.com/colors/brands/nintendo-com), Datadog (https://brandsweets.com/colors/brands/datadoghq-com), MLB (https://brandsweets.com/colors/brands/mlb-com). — https://brandsweets.com/colors/firebrick
- **Royal Blue** #4169e1 [pool] — Royal Blue is paired with #331b9d in 7 real palettes, including Nivea's brand system and Discord's brand system, as the supporting colour. Seen in: Nivea (https://brandsweets.com/colors/brands/nivea-com), Discord (https://brandsweets.com/colors/brands/discord), Nokia (https://brandsweets.com/colors/brands/nokia-com), NHL (https://brandsweets.com/colors/brands/nhl-com). — https://brandsweets.com/colors/royalblue
- **Olive Green** #808000 [harmony: complementary] — Olive Green sits directly opposite #331b9d 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/olive
- **Charcoal** #36454f [role, pool] — Charcoal is the text near-black for #331b9d: softer than #000 and cool enough to feel like part of the same palette. Seen in: dbt Labs (https://brandsweets.com/colors/brands/getdbt-com), Boeing (https://brandsweets.com/colors/brands/boeing-com). — https://brandsweets.com/colors/charcoal

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

- On white (#ffffff): 11.77:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 1.78:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #7a62e4 (4.69:1); AA: background → #a1a1a1 (4.56:1); AAA: text → #9b89eb (7.17:1); AAA: background → #c9c9c9 (7.11:1)

## Brands using this color

- **dbt Labs** — accent #3d189a (Δ 1.958) — https://brandsweets.com/colors/brands/getdbt-com

## Fonts for this mood

- technical: https://brandsweets.com/fonts/mood/technical
- modern: https://brandsweets.com/fonts/mood/modern

## Palette tool

Open this color locked as the lead with four explored companions: https://brandsweets.com/palettes/new/331b9d-a89cc4-dfb34e-281f2d-e9ecf1?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: "#331b9d" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.