Color
#378cb3
#378cb3rgb(55, 140, 179)hsl(199, 53%, 46%)oklch(0.606 0.1 231.7)Colors that go with #378cb3
Charcoal, Copper and Crimson lead the list. Each partner is a real named colour with the reason it works — a wheel relationship, a neutral that carries it, or a pairing lifted from a palette or brand system that actually shipped — and every pair opens in the palette tool.
Charcoal #36454f
neutralshippedCharcoal is the text near-black for #378cb3: softer than #000 and cool enough to feel like part of the same palette.
Copper #b87333
complementaryshippedCopper sits directly opposite #378cb3 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Crimson #dc143c
split-complementshippedCrimson is a split-complement of #378cb3: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Royal Blue #4169e1
analogousshippedRoyal Blue is #378cb3's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Amber #ffbf00
shippedAmber is paired with #378cb3 in 7 real palettes, including Beach Hut and Wired's brand system, as the supporting colour.
Blue #0000ff
shipped4 real palettes, including Qualcomm's brand system and Readymag's brand system put Blue beside #378cb3, as the accent.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #378cb3: 5 real palettes, including Hershey's's brand system and Glacier, as the supporting colour.
Deep Sky Blue #00bfff
shippedDesigners have shipped Deep Sky Blue with #378cb3: 7 real palettes, including Telegram's brand system and Deep Water, as the lead colour.
Real palettes that use #378cb3
Tints & shades
Harmonies
Contrast
| #378cb3 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 3.77:1 | fail | pass | fail | |
Aaon black | 5.56:1 | pass | pass | fail |
|
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #378cb3 as the background.
Brands using this color
No public brand in the corpus uses this exact color yet. Extract a brand to add one.
Fonts for this mood
#378cb3 reads as cool, modern. The font library is tagged with the same vocabulary:
Point any MCP client at the shared colors endpoint and your agent gets the same engine as this page — direct_palette, edit_direction, check_palette, check_contrast — read-only, no key. Every direction it proposes comes with a /colors/d/… link: open it, lock what you like, paste the link back, and the agent edits rather than re-rolls.
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
›analyze #378cb3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/378cb3-9cb3c4-df4e66-1f232d-e9f1f0?lock=0&style=vibrantWant the agent to remember your picks and write them into a living brand? Create a free BrandSweets workspace.
Machine-readable: color.md