# #331b55

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

## Values

- Hex: `#331b55`
- RGB: rgb(51, 27, 85)
- HSL: hsl(265, 52%, 22%)
- OKLCH: oklch(0.289 0.101 299)
- Relative luminance: 0.0214
- Nearest named color: Fabric of Space (#341758, Δ 1.063) — https://brandsweets.com/colors/fabric-of-space
- Moods: cool, dark, luxury, bold, modern
- Page: https://brandsweets.com/colors/331b55

## Tints & shades

- Tints (toward white): #462574, #562d8f, #6937ae, #7a45c4, #9064ce, #a683d8, #ba9ee0, #d0bdea, #e3d8f3, #f9f7fd
- Shades (toward black): #2f184e, #2a1646, #281542, #23123a, #1e1032, #1a0d2b, #150b23, #130a1f, #0e0717, #090510

## Harmonies

- Complementary: #3d551b
- Analogous: #1b2055, #501b55
- Triadic: #55331b, #1b5533
- Split-complementary: #55501b, #20551b
- Tetradic: #551b20, #3d551b, #1b5550

## Colors that go with #331b55

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 #331b55: softer than #000 and cool enough to feel like part of the same palette. Seen in: Microsoft (https://brandsweets.com/colors/brands/microsoft-com), Plaid (https://brandsweets.com/colors/brands/plaid-com), CeraVe (https://brandsweets.com/colors/brands/cerave-com), Squarespace (https://brandsweets.com/colors/brands/squarespace-com). — https://brandsweets.com/colors/charcoal
- **Royal Blue** #4169e1 [harmony, pool: analogous] — Royal Blue is #331b55's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Telehealth (https://brandsweets.com/palettes/modern#telehealth), Confluent (https://brandsweets.com/colors/brands/confluent-io), GEICO (https://brandsweets.com/colors/brands/geico-com), Spectrum (https://brandsweets.com/colors/brands/spectrum-com). — https://brandsweets.com/colors/royalblue
- **Sea Green** #2e8b57 [harmony, pool: split] — Sea Green is a split-complement of #331b55: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Asana (https://brandsweets.com/colors/brands/asana-com), Subaru (https://brandsweets.com/colors/brands/subaru-com), Wellness (https://brandsweets.com/palettes/warm#wellness), Mushroom (https://brandsweets.com/palettes/neutral#mushroom). — https://brandsweets.com/colors/seagreen
- **Teal** #008080 [harmony, pool: triadic] — Teal completes a triad with #331b55 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash. Seen in: Lufthansa (https://brandsweets.com/colors/brands/lufthansa-com), Alpine (https://brandsweets.com/palettes/cool#alpine), Clinic (https://brandsweets.com/palettes/clean#clinic), Mid-Century (https://brandsweets.com/palettes/warm#mid-century). — https://brandsweets.com/colors/teal
- **Amber** #ffbf00 [pool] — Amber is paired with #331b55 in 6 real palettes, including Southwest Airlines's brand system and Beach Hut, as the accent. Seen in: Southwest Airlines (https://brandsweets.com/colors/brands/southwest-com), Beach Hut (https://brandsweets.com/palettes/light#beach-hut), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com), Wikipedia (https://brandsweets.com/colors/brands/wikipedia-org). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 13 real palettes, including Sketch's brand system and Monzo's brand system put Blue beside #331b55, 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), Readymag (https://brandsweets.com/colors/brands/readymag-com). — https://brandsweets.com/colors/blue
- **Burlywood** #deb887 [pool] — Burlywood is paired with #331b55 in 4 real palettes, including Coastal and Polaroid, as the accent. Seen in: Coastal (https://brandsweets.com/palettes/cool#coastal), Polaroid (https://brandsweets.com/palettes/light#polaroid), Kiln (https://brandsweets.com/palettes/dark#kiln), Chalkboard (https://brandsweets.com/palettes/dark#chalkboard). — https://brandsweets.com/colors/burlywood
- **Cadet Blue** #5f9ea0 [pool] — Designers have shipped Cadet Blue with #331b55: 9 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

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

- On white (#ffffff): 14.7:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 1.43:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #8b5ccc (4.5:1); AA: background → #8f8f8f (4.55:1); AAA: text → #a987d9 (7.15:1); AAA: background → #b3b3b3 (7.01:1)

## 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/331b55-b19cc4-dfd54e-2b1f2d-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: "#331b55" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.