# #331b5f

A color — cool, dark, luxury, bold, modern. Deterministic analysis from BrandSweets (no inference).

## Values

- Hex: `#331b5f`
- RGB: rgb(51, 27, 95)
- HSL: hsl(261, 56%, 24%)
- OKLCH: oklch(0.298 0.114 294.6)
- Relative luminance: 0.0231
- Nearest named color: Fabric of Space (#341758, Δ 1.533) — https://brandsweets.com/colors/fabric-of-space
- Moods: cool, dark, luxury, bold, modern
- Page: https://brandsweets.com/colors/331b5f

## Tints & shades

- Tints (toward white): #42237b, #532c9b, #6234b7, #7648cb, #8b64d3, #a080db, #b8a0e4, #ccbbec, #e4dbf5, #f9f7fd
- Shades (toward black): #2f1958, #2a1650, #261448, #221240, #1e1038, #190d30, #150b28, #110920, #0d0718, #080410

## Harmonies

- Complementary: #475f1b
- Analogous: #1b255f, #551b5f
- Triadic: #5f331b, #1b5f33
- Split-complementary: #5f551b, #255f1b
- Tetradic: #5f1b25, #475f1b, #1b5f55

## Colors that go with #331b5f

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 #331b5f: softer than #000 and cool enough to feel like part of the same palette. Seen in: CeraVe (https://brandsweets.com/colors/brands/cerave-com), Plaid (https://brandsweets.com/colors/brands/plaid-com), Microsoft (https://brandsweets.com/colors/brands/microsoft-com), Tumblr (https://brandsweets.com/colors/brands/tumblr-com). — https://brandsweets.com/colors/charcoal
- **Royal Blue** #4169e1 [harmony, pool: analogous] — Royal Blue is #331b5f's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Discord (https://brandsweets.com/colors/brands/discord), Confluent (https://brandsweets.com/colors/brands/confluent-io), Telehealth (https://brandsweets.com/palettes/modern#telehealth), GEICO (https://brandsweets.com/colors/brands/geico-com). — https://brandsweets.com/colors/royalblue
- **Blue** #0000ff [pool] — 8 real palettes, including Sketch's brand system and Monzo's brand system put Blue beside #331b5f, as the accent. Seen in: Sketch (https://brandsweets.com/colors/brands/sketch-com), Monzo (https://brandsweets.com/colors/brands/monzo-com), Penpot (https://brandsweets.com/colors/brands/penpot-app), Alaska Airlines (https://brandsweets.com/colors/brands/alaskaair-com). — https://brandsweets.com/colors/blue
- **Cadet Blue** #5f9ea0 [pool] — Designers have shipped Cadet Blue with #331b5f: 6 real palettes, including SoFi's brand system and Open House, as the supporting colour. Seen in: SoFi (https://brandsweets.com/colors/brands/sofi-com), Open House (https://brandsweets.com/palettes/clean#open-house), Coastal (https://brandsweets.com/palettes/cool#coastal), Dusk (https://brandsweets.com/palettes/cool#dusk). — https://brandsweets.com/colors/cadetblue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #331b5f: 7 real palettes, including Blue Mono and Purina Pro Plan's brand system, as the lead colour. Seen in: Blue Mono (https://brandsweets.com/palettes/cool#blue-mono), Purina Pro Plan (https://brandsweets.com/colors/brands/chewy-com), MLB (https://brandsweets.com/colors/brands/mlb-com), Fintech Trust (https://brandsweets.com/palettes/cool#fintech-trust). — https://brandsweets.com/colors/cobalt
- **Cornflower Blue** #6495ed [pool] — Designers have shipped Cornflower Blue with #331b5f: 4 real palettes, including Blue Mono and Peacock's brand system, as the supporting colour. Seen in: Blue Mono (https://brandsweets.com/palettes/cool#blue-mono), Peacock (https://brandsweets.com/colors/brands/peacocktv-com), Blizzard (https://brandsweets.com/colors/brands/blizzard-com), Arctic (https://brandsweets.com/palettes/clean#arctic). — https://brandsweets.com/colors/cornflowerblue
- **Crimson** #dc143c [pool] — Crimson is paired with #331b5f in 11 real palettes, including Casper Sleep's brand system and Marvel's brand system, as the lead colour. Seen in: Casper Sleep (https://brandsweets.com/colors/brands/casper-com), Marvel (https://brandsweets.com/colors/brands/marvel-com), Nintendo (https://brandsweets.com/colors/brands/nintendo-com), Frost & Ember (https://brandsweets.com/palettes/bold#frost-and-ember). — https://brandsweets.com/colors/crimson
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #331b5f: 4 real palettes, including Kraken's brand system and Vimeo's brand system, as the accent. Seen in: Kraken (https://brandsweets.com/colors/brands/kraken-com), Vimeo (https://brandsweets.com/colors/brands/vimeo-com), Deep Water (https://brandsweets.com/palettes/dark#deep-water), Astro (https://brandsweets.com/colors/brands/astro-build). — https://brandsweets.com/colors/deepskyblue

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

- On white (#ffffff): 14.36:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 1.46:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #8860d2 (4.65:1); AA: background → #919191 (4.56:1); AAA: text → #a688dd (7.19:1); AAA: background → #b5b5b5 (7:1)

## Fonts for this mood

- luxury: https://brandsweets.com/fonts/mood/luxury
- bold: https://brandsweets.com/fonts/mood/bold
- 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/331b5f-af9cc4-dfcb4e-2a1f2d-e9eaf1?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: "#331b5f" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.