Color
#123cd3
#123cd3rgb(18, 60, 211)hsl(227, 84%, 45%)oklch(0.45 0.232 264.8)Colors that go with #123cd3
Medium Sea Green, Midnight Blue and Slate Gray 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.
Medium Sea Green #3cb371
shippedMedium Sea Green is paired with #123cd3 in 4 real palettes, including Indigo SaaS and Console Light, as the accent — a combination designers have actually shipped, not a computed rotation.
Midnight Blue #191970
shippedMidnight Blue is paired with #123cd3 in 4 real palettes, including Blue Mono and Monzo's brand system, as the text colour against it — a combination designers have actually shipped, not a computed rotation.
Slate Gray #708090
shippedSlate Gray is paired with #123cd3 in 4 real palettes, including Campus and Ink & Paper, as the supporting colour — a combination designers have actually shipped, not a computed rotation.
Olive Green #808000
complementaryOlive Green sits directly opposite #123cd3 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Charcoal #36454f
neutralshippedCharcoal is the text near-black for #123cd3: softer than #000 and cool enough to feel like part of the same palette.
Royal Blue #4169e1
shippedRoyal Blue is paired with #123cd3 in 3 real palettes, including Behance's brand system and Dropbox's brand system, as the lead colour — a combination designers have actually shipped, not a computed rotation.
Steel Blue #4682b4
analogousshippedSteel Blue is #123cd3's neighbour on the wheel, so the two read as one family — use it for hover states, gradients and secondary surfaces.
Sienna #a0522d
split-complementSienna is a split-complement of #123cd3: nearly opposite, so it still pops against it, without the vibrating edge of a true complement.
Real palettes that use #123cd3
Tints & shades
Harmonies
Contrast
| #123cd3 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 8.04:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 2.61:1 | fail | fail | fail |
Fixes keep hue and saturation and move lightness only, so the suggestion stays on-brand. Ratios are symmetric: the same numbers apply with #123cd3 as the background.
Brands using this color
Fonts for this mood
#123cd3 reads as cool, vivid, technical. 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 #123cd3 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
/palettes/new/123cd3-9ca0c4-df7a4e-221f2d-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