# #397bf3

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

## Values

- Hex: `#397bf3`
- RGB: rgb(57, 123, 243)
- HSL: hsl(219, 89%, 59%)
- OKLCH: oklch(0.606 0.193 261.2)
- Relative luminance: 0.2151
- Nearest named color: Blue Öyster Cult (#5577ee, Δ 2.597) — https://brandsweets.com/colors/blue-oyster-cult
- Moods: cool, vivid, technical, modern
- Page: https://brandsweets.com/colors/397bf3

## Tints & shades

- Tints (toward white): #4d87f5, #6094f6, #73a1f7, #87aef8, #9abbf9, #a8c5fa, #bcd2fb, #cfdffc, #e2ecfd, #f5f9fe
- Shades (toward black): #216af2, #0d5ae7, #0c50cf, #0a45b2, #093c9a, #07317d, #062765, #041c48, #031330, #010713

## Harmonies

- Complementary: #f3b239
- Analogous: #39d8f3, #5539f3
- Triadic: #f3397b, #7bf339
- Split-complementary: #f35539, #d8f339
- Tetradic: #f339d8, #f3b239, #39f355

## Colors that go with #397bf3

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 #397bf3: softer than #000 and cool enough to feel like part of the same palette. Seen in: Disney (https://brandsweets.com/colors/brands/disney-com), Docker (https://brandsweets.com/colors/brands/docker-com), Zoom (https://brandsweets.com/colors/brands/zoom-us), Hinge (https://brandsweets.com/colors/brands/hinge-co). — https://brandsweets.com/colors/charcoal
- **Crimson** #dc143c [harmony, pool: triadic] — Crimson completes a triad with #397bf3 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash. Seen in: Behance (https://brandsweets.com/colors/brands/behance-net), WWE (https://brandsweets.com/colors/brands/wwe-com), Foot Locker (https://brandsweets.com/colors/brands/footlocker-com), Pizza Hut (https://brandsweets.com/colors/brands/pizzahut-com). — https://brandsweets.com/colors/crimson
- **Copper** #b87333 [harmony, pool: complementary] — Copper sits directly opposite #397bf3 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Notion (https://brandsweets.com/colors/brands/notion). — https://brandsweets.com/colors/copper
- **Amber** #ffbf00 [pool] — Amber is paired with #397bf3 in 11 real palettes, including Google's brand system and Walmart's brand system, as the accent. Seen in: Google (https://brandsweets.com/colors/brands/google-com), Walmart (https://brandsweets.com/colors/brands/walmart-com), Heatwave (https://brandsweets.com/palettes/warm#heatwave), Mastodon hosted on mastodon.social (https://brandsweets.com/colors/brands/mastodon-social). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 14 real palettes, including Cargo's brand system and Samsung's brand system put Blue beside #397bf3, as the accent. Seen in: Cargo (https://brandsweets.com/colors/brands/cargo-site), Samsung (https://brandsweets.com/colors/brands/samsung-com), Penpot (https://brandsweets.com/colors/brands/penpot-app), Readymag (https://brandsweets.com/colors/brands/readymag-com). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #397bf3: 10 real palettes, including Carrefour's brand system and Behance's brand system, as the accent. Seen in: Carrefour (https://brandsweets.com/colors/brands/carrefour-com), Behance (https://brandsweets.com/colors/brands/behance-net), Nokia (https://brandsweets.com/colors/brands/nokia-com), Nivea (https://brandsweets.com/colors/brands/nivea-com). — https://brandsweets.com/colors/cobalt
- **Deep Sky Blue** #00bfff [pool] — Designers have shipped Deep Sky Blue with #397bf3: 9 real palettes, including Patreon's brand system and Venmo's brand system, as the supporting colour. Seen in: Patreon (https://brandsweets.com/colors/brands/patreon-com), Venmo (https://brandsweets.com/colors/brands/venmo-com), Elastic (https://brandsweets.com/colors/brands/elastic-co), Astro (https://brandsweets.com/colors/brands/astro-build). — https://brandsweets.com/colors/deepskyblue
- **Denim** #1560bd [pool] — Designers have shipped Denim with #397bf3: 18 real palettes, including Coursera's brand system and Guinness's brand system, as the accent. Seen in: Coursera (https://brandsweets.com/colors/brands/coursera-org), Guinness (https://brandsweets.com/colors/brands/guinness-com), Fivetran blue (https://brandsweets.com/colors/brands/fivetran-com), Venmo (https://brandsweets.com/colors/brands/venmo-com). — https://brandsweets.com/colors/denim

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

- On white (#ffffff): 3.96:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #266ef2 (4.57:1); AA: background → #171717 (4.53:1); AAA: text → #0c4fca (7.03:1)
- On black (#000000): 5.3:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #6094f6 (7.06:1)

## Brands using this color

- **PostHog** — secondary #2f80fa (Δ 1.546) — https://brandsweets.com/colors/brands/posthog-com

## Curated palettes containing it

- **Playground** (bold, playful, warm) — #ff8c00, #3b82f6, #22c55e, #fff8e7, #1d1d1d — Orange, blue and green — the colors of playground equipment; loud, cheerful, obviously for kids. — tool: https://brandsweets.com/palettes/new/ff8c00-3b82f6-22c55e-fff8e7-1d1d1d — collection: https://brandsweets.com/palettes/bold

## 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/397bf3-9ca5c4-df664e-211f2d-e9f0f1?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: "#397bf3" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.