# #377ea4

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

## Values

- Hex: `#377ea4`
- RGB: rgb(55, 126, 164)
- HSL: hsl(201, 50%, 43%)
- OKLCH: oklch(0.565 0.092 235.1)
- Relative luminance: 0.1841
- Nearest named color: Cry Me a River (#427898, Δ 2.223) — https://brandsweets.com/colors/cry-me-a-river
- Moods: cool, modern
- Page: https://brandsweets.com/colors/377ea4

## Tints & shades

- Tints (toward white): #3e90bb, #4f9bc4, #66a8cc, #79b3d2, #90c0da, #a3cbe0, #bad8e8, #cde3ee, #e4f0f6, #f7fbfc
- Shades (toward black): #327295, #2d6786, #285b77, #224f67, #1f465c, #1a3b4d, #142f3d, #0f232e, #0a171f, #050c0f

## Harmonies

- Complementary: #a45d37
- Analogous: #37a494, #3747a4
- Triadic: #a4377e, #7ea437
- Split-complementary: #a43747, #a49437
- Tetradic: #9437a4, #a45d37, #47a437

## Colors that go with #377ea4

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 #377ea4: softer than #000 and cool enough to feel like part of the same palette. Seen in: Beach Hut (https://brandsweets.com/palettes/light#beach-hut), Auth0 (https://brandsweets.com/colors/brands/auth0-com), Campus (https://brandsweets.com/palettes/friendly#campus), Plaid (https://brandsweets.com/colors/brands/plaid-com). — https://brandsweets.com/colors/charcoal
- **Crimson** #dc143c [harmony, pool: split] — Crimson is a split-complement of #377ea4: nearly opposite, so it still pops against it, without the vibrating edge of a true complement. Seen in: Retro Pop (https://brandsweets.com/palettes/playful#retro-pop), Wendy's (https://brandsweets.com/colors/brands/wendys-com), Redfin (https://brandsweets.com/colors/brands/redfin-com), NASCAR (https://brandsweets.com/colors/brands/nascar-com). — https://brandsweets.com/colors/crimson
- **Royal Blue** #4169e1 [harmony, pool: analogous] — Royal Blue is #377ea4's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces. Seen in: Slate Workspace (https://brandsweets.com/palettes/minimal#slate-workspace), Stripe (https://brandsweets.com/colors/brands/stripe), Guinness (https://brandsweets.com/colors/brands/guinness-com), GitHub (https://brandsweets.com/colors/brands/github). — https://brandsweets.com/colors/royalblue
- **Sienna** #a0522d [harmony, pool: complementary] — Sienna sits directly opposite #377ea4 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight. Seen in: Dyson (https://brandsweets.com/colors/brands/dyson-com). — https://brandsweets.com/colors/sienna
- **Amber** #ffbf00 [pool] — Amber is paired with #377ea4 in 8 real palettes, including Beach Hut and Wired's brand system, as the supporting colour. Seen in: Beach Hut (https://brandsweets.com/palettes/light#beach-hut), Wired (https://brandsweets.com/colors/brands/wired-com), Lemon Squeezy (https://brandsweets.com/colors/brands/lemonsqueezy-com), McDonald's (https://brandsweets.com/colors/brands/mcdonalds-com). — https://brandsweets.com/colors/amber
- **Blue** #0000ff [pool] — 4 real palettes, including Activision's brand system and Pixar's brand system put Blue beside #377ea4, as the accent. Seen in: Activision (https://brandsweets.com/colors/brands/activision-com), Pixar (https://brandsweets.com/colors/brands/pixar-com), Qualcomm (https://brandsweets.com/colors/brands/qualcomm-com), Readymag (https://brandsweets.com/colors/brands/readymag-com). — https://brandsweets.com/colors/blue
- **Cobalt Blue** #0047ab [pool] — Designers have shipped Cobalt Blue with #377ea4: 8 real palettes, including Glacier and Hershey's's brand system, as the accent. Seen in: Glacier (https://brandsweets.com/palettes/cool#glacier), Hershey's (https://brandsweets.com/colors/brands/hersheys-com), Fintech Trust (https://brandsweets.com/palettes/cool#fintech-trust), General Mills (https://brandsweets.com/colors/brands/generalmills-com). — https://brandsweets.com/colors/cobalt
- **Copper** #b87333 [pool] — Designers have shipped Copper with #377ea4: 5 real palettes, including Riverbed and Notion's brand system, as the accent. Seen in: Riverbed (https://brandsweets.com/palettes/muted#riverbed), Notion (https://brandsweets.com/colors/brands/notion), Dusk (https://brandsweets.com/palettes/cool#dusk), Wellness (https://brandsweets.com/palettes/warm#wellness). — https://brandsweets.com/colors/copper

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

- On white (#ffffff): 4.48:1 — AA fail, AA-large pass, AAA fail. Fix: AA: text → #367ba1 (4.66:1); AA: background → #050505 (4.54:1); AAA: text → #295e7a (7.06:1)
- On black (#000000): 4.68:1 — AA pass, AA-large pass, AAA fail. Fix: AAA: text → #539dc6 (7.01:1)

## Curated palettes containing it

- **Retro Pop** (playful, bold, warm) — #e63946, #457b9d, #f4a261, #fff4e0, #23201c — Fifties-diner red and steel blue with a peach — nostalgic pop that still passes contrast. — tool: https://brandsweets.com/palettes/new/e63946-457b9d-f4a261-fff4e0-23201c — collection: https://brandsweets.com/palettes/playful

## 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/377ea4-9cb1c4-df4e62-1f222d-e9f1f0?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: "#377ea4" })`), `check_contrast` (with fixes), `generate_palette` (explore around locks), `suggest_palette` (mood/industry → curated-first), `list_palettes`.