Color
#3971b1
#3971b1rgb(57, 113, 177)hsl(212, 51%, 46%)oklch(0.541 0.117 253.4)Colors that go with #3971b1
Charcoal, Sea Green and Sienna 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 #3971b1: softer than #000 and cool enough to feel like part of the same palette.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #3971b1 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Sienna #a0522d
complementaryshippedSienna sits directly opposite #3971b1 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Amber #ffbf00
shippedAmber is paired with #3971b1 in 9 real palettes, including Lemon Squeezy's brand system and McDonald's's brand system, as the lead colour.
Blue #0000ff
shipped13 real palettes, including Activision's brand system and Pixar's brand system put Blue beside #3971b1, as the accent.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #3971b1: 10 real palettes, including Glacier and General Mills's brand system, as the accent.
Cornflower Blue #6495ed
shippedDesigners have shipped Cornflower Blue with #3971b1: 4 real palettes, including Coca-Cola's brand system and NBA's brand system, as the supporting colour.
Crimson #dc143c
shippedCrimson is paired with #3971b1 in 17 real palettes, including State Farm's brand system and McDonald's's brand system, as the lead colour.
Real palettes that use #3971b1
Tints & shades
Harmonies
Contrast
| #3971b1 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 5.03:1 | pass | pass | fail |
|
Aaon black | 4.17:1 | fail | 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 #3971b1 as the background.
Brands using this color
Fonts for this mood
#3971b1 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 #3971b1 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/3971b1-9caac4-df564e-1f202d-e9f1f1?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