Playground
Open in tool →Orange, blue and green — the colors of playground equipment; loud, cheerful, obviously for kids.
Color
#5181f0
#5181f0
hex
#5181f0rgb
rgb(81, 129, 240)hsl
hsl(222, 84%, 63%)oklch
oklch(0.626 0.175 264.4)Closest name: Blue Öyster Cult (#5577ee)Relative luminance 0.2374
Colors that go with #5181f0
Charcoal, Red and Amber 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 #5181f0: softer than #000 and cool enough to feel like part of the same palette.
Red #ff0000
triadicshippedRed completes a triad with #5181f0 — three hues spaced evenly round the wheel, the classic way to get energy into a palette without a clash.
Amber #ffbf00
shippedAmber is paired with #5181f0 in 11 real palettes, including Google's brand system and Heatwave, as the accent.
Blue #0000ff
shipped13 real palettes, including Qualcomm's brand system and Readymag's brand system put Blue beside #5181f0, as the accent.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #5181f0: 10 real palettes, including Carrefour's brand system and Behance's brand system, as the accent.
Crimson #dc143c
shippedCrimson is paired with #5181f0 in 11 real palettes, including Behance's brand system and Pizza Hut's brand system, as the accent.
Deep Sky Blue #00bfff
shippedDesigners have shipped Deep Sky Blue with #5181f0: 10 real palettes, including Patreon's brand system and Venmo's brand system, as the supporting colour.
Denim #1560bd
shippedDesigners have shipped Denim with #5181f0: 18 real palettes, including Coursera's brand system and Venmo's brand system, as the accent.
Real palettes that use #5181f0
Tints & shades
Harmonies
Contrast
| #5181f0 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 3.65:1 | fail | pass | fail | |
Aaon black | 5.75:1 | 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 #5181f0 as the background.
Brands using this color
Palettes built around it
Fonts for this mood
#5181f0 reads as cool, vivid, technical. The font library is tagged with the same vocabulary:
mcpConnect your agent — build around #5181f0
live endpointPoint 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.
endpoint
https://mcp.brandsweets.com/colors/mcpclaude mcp add --transport http brandsweets-colors https://mcp.brandsweets.com/colors/mcp
try this prompt
›analyze #5181f0 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/5181f0-9ca3c4-df6e4e-211f2d-e9eff1?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