# #663db3

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

## Values

- Hex: `#663db3`
- RGB: rgb(102, 61, 179)
- HSL: hsl(261, 49%, 47%)
- OKLCH: oklch(0.474 0.178 294.6)
- Relative luminance: 0.0942
- Nearest named color: rebeccapurple (#663399, Δ 4.591) — https://brandsweets.com/colors/rebeccapurple
- Moods: cool, modern
- Page: https://brandsweets.com/colors/663db3

## Tints & shades

- Tints (toward white): #7349c1, #815cc7, #906fce, #9e82d4, #b098dc, #bfabe2, #cdbee9, #dcd1ef, #ebe4f6, #f9f7fc
- Shades (toward black): #5e38a3, #533190, #4a2c81, #412772, #392263, #2e1b50, #251641, #1c1131, #110a1e, #09050f

## Harmonies

- Complementary: #89b33d
- Analogous: #3d4fb3, #a13db3
- Triadic: #b3663d, #3db366
- Split-complementary: #b3a13d, #4fb33d
- Tetradic: #b33d4f, #89b33d, #3db3a1

## Colors that go with #663db3

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 #663db3: 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 #663db3'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), Chase (https://brandsweets.com/colors/brands/chase-com). — https://brandsweets.com/colors/royalblue
- **Sea Green** #2e8b57 [harmony, pool: split] — Sea Green is a split-complement of #663db3: 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 #663db3 in 9 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 #663db3: 9 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), Warbyparker (https://brandsweets.com/colors/brands/warbyparker-com), Unilever (https://brandsweets.com/colors/brands/unilever-com). — https://brandsweets.com/colors/denim
- **Firebrick** #b22222 [pool] — Designers have shipped Firebrick with #663db3: 4 real palettes, including Datadog's brand system and Campbell's's brand system, as the accent. Seen in: Datadog (https://brandsweets.com/colors/brands/datadoghq-com), Campbell's (https://brandsweets.com/colors/brands/campbells-com), MLB (https://brandsweets.com/colors/brands/mlb-com), Nissan (https://brandsweets.com/colors/brands/nissanusa-com). — https://brandsweets.com/colors/firebrick
- **Midnight Blue** #191970 [pool] — 10 real palettes, including Kraken's brand system and Paramount+'s brand system put Midnight Blue beside #663db3, 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), Panasonic (https://brandsweets.com/colors/brands/panasonic-com). — https://brandsweets.com/colors/midnightblue
- **Red** #ff0000 [pool] — Red is paired with #663db3 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

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

- On white (#ffffff): 7.28:1 — AA pass, AA-large pass, AAA pass
- On black (#000000): 2.88:1 — AA fail, AA-large fail, AAA fail. Fix: AA: text → #8763ca (4.67:1); AA: background → #cccccc (4.54:1); AAA: text → #a489d7 (7.14:1); AAA: background → #fcfcfc (7.1:1)

## Brands using this color

- **Deno** — primary #6639ba (Δ 1.359) — https://brandsweets.com/colors/brands/deno-com
- **Deno** — accent #6639ba (Δ 1.359) — 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/663db3-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: "#663db3" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.