# #663bb5

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

## Values

- Hex: `#663bb5`
- RGB: rgb(102, 59, 181)
- HSL: hsl(261, 51%, 47%)
- OKLCH: oklch(0.473 0.182 294.6)
- Relative luminance: 0.0929
- Nearest named color: rebeccapurple (#663399, Δ 4.744) — https://brandsweets.com/colors/rebeccapurple
- Moods: cool, modern
- Page: https://brandsweets.com/colors/663bb5

## Tints & shades

- Tints (toward white): #7246c3, #8159c9, #8f6dd0, #9e80d6, #b097dd, #beaae4, #cdbeea, #dcd1f0, #eae4f6, #f9f7fd
- Shades (toward black): #5d36a6, #522f92, #492a83, #412574, #382064, #2d1a51, #251541, #1c1032, #110a1f, #09050f

## Harmonies

- Complementary: #8ab53b
- Analogous: #3b4db5, #a33bb5
- Triadic: #b5663b, #3bb566
- Split-complementary: #b5a33b, #4db53b
- Tetradic: #b53b4d, #8ab53b, #3bb5a3

## Colors that go with #663bb5

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 #663bb5: softer than #000 and cool enough to feel like part of the same palette. Seen in: Hinge (https://brandsweets.com/colors/brands/hinge-co), Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com), Starlink (https://brandsweets.com/colors/brands/starlink-com), UEFA (https://brandsweets.com/colors/brands/uefa-com). — https://brandsweets.com/colors/charcoal
- **Royal Blue** #4169e1 [harmony, pool: analogous] — Royal Blue is #663bb5's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Wayfair (https://brandsweets.com/colors/brands/wayfair-com), Fivetran blue (https://brandsweets.com/colors/brands/fivetran-com), Guinness (https://brandsweets.com/colors/brands/guinness-com), NHL (https://brandsweets.com/colors/brands/nhl-com). — https://brandsweets.com/colors/royalblue
- **Sea Green** #2e8b57 [harmony, pool: split] — Sea Green is a split-complement of #663bb5: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Jack Daniel's (https://brandsweets.com/colors/brands/jackdaniels-com), Netflix (https://brandsweets.com/colors/brands/netflix), Paramount+ (https://brandsweets.com/colors/brands/paramountplus-com), Intel (https://brandsweets.com/colors/brands/intel-com). — https://brandsweets.com/colors/seagreen
- **Crimson** #dc143c [pool] — Crimson is paired with #663bb5 in 7 real palettes, including Wells Fargo's brand system and Gemstone, as the lead colour. Seen in: Wells Fargo (https://brandsweets.com/colors/brands/wellsfargo-com), Gemstone (https://brandsweets.com/palettes/vivid#gemstone), Netflix (https://brandsweets.com/colors/brands/netflix), Ulta Beauty (https://brandsweets.com/colors/brands/ulta-com). — https://brandsweets.com/colors/crimson
- **Denim** #1560bd [pool] — Designers have shipped Denim with #663bb5: 7 real palettes, including Linkedin's brand system and Slack's brand system, as the lead colour. Seen in: Linkedin (https://brandsweets.com/colors/brands/linkedin-com), Slack (https://brandsweets.com/colors/brands/slack-com), Unilever (https://brandsweets.com/colors/brands/unilever-com), Warbyparker (https://brandsweets.com/colors/brands/warbyparker-com). — https://brandsweets.com/colors/denim
- **Midnight Blue** #191970 [pool] — 9 real palettes, including Kraken's brand system and Paramount+'s brand system put Midnight Blue beside #663bb5, as the lead colour. Seen in: Kraken (https://brandsweets.com/colors/brands/kraken-com), Paramount+ (https://brandsweets.com/colors/brands/paramountplus-com), Purina Pro Plan (https://brandsweets.com/colors/brands/chewy-com), Blue Mono (https://brandsweets.com/palettes/cool#blue-mono). — https://brandsweets.com/colors/midnightblue
- **Red** #ff0000 [pool] — Red is paired with #663bb5 in 4 real palettes, including Twitch's brand system and L'Oréal's brand system, as the accent. Seen in: Twitch (https://brandsweets.com/colors/brands/twitch-tv), L'Oréal (https://brandsweets.com/colors/brands/loreal-com), Walgreens (https://brandsweets.com/colors/brands/walgreens-com), ElevenLabs (https://brandsweets.com/colors/brands/elevenlabs-io). — https://brandsweets.com/colors/red
- **Tomato** #ff6347 [pool] — 5 real palettes, including GitLab's brand system and Fivetran blue's brand system put Tomato beside #663bb5, as the lead colour. Seen in: GitLab (https://brandsweets.com/colors/brands/gitlab), Fivetran blue (https://brandsweets.com/colors/brands/fivetran-com), Etsy (https://brandsweets.com/colors/brands/etsy-com), FedEx (https://brandsweets.com/colors/brands/fedex-com). — https://brandsweets.com/colors/tomato

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

- On white (#ffffff): 7.35:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 2.86:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #8661cc (4.6:1); AA: background → #cccccc (4.58:1); AAA: text → #a488d8 (7.09:1); AAA: background → #fafafa (7.04:1)

## Brands using this color

- **Deno** — primary #6639ba (Δ 0.879) — https://brandsweets.com/colors/brands/deno-com
- **Deno** — accent #6639ba (Δ 0.879) — https://brandsweets.com/colors/brands/deno-com

## Fonts for this mood

- 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/663bb5-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: "#663bb5" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.