Harbour
Open in tool →Steel blue and haze with a buoy orange on a pale grey — the maritime palette every port town uses for a reason.
Color
#455a78
#455a78
hex
#455a78rgb
rgb(69, 90, 120)hsl
hsl(215, 27%, 37%)oklch
oklch(0.463 0.056 257.3)Closest name: Deep Indigo (#4c567a)Relative luminance 0.0993
Colors that go with #455a78
Sea Green, Sienna and Blue 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.
Sea Green #2e8b57
triadicshippedSea Green completes a triad with #455a78 — 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 #455a78 on the wheel — the strongest contrast one hue can give another, so use it small: a button, a link colour, one highlight.
Blue #0000ff
shipped7 real palettes, including Tesco's brand system and CVS's brand system put Blue beside #455a78, as the supporting colour.
Cadet Blue #5f9ea0
shippedDesigners have shipped Cadet Blue with #455a78: 4 real palettes, including Dusk and Open House, as the supporting colour.
Cobalt Blue #0047ab
shippedDesigners have shipped Cobalt Blue with #455a78: 4 real palettes, including Fintech Trust and Unilever's brand system, as the lead colour.
Copper #b87333
shippedDesigners have shipped Copper with #455a78: 4 real palettes, including Dusk and Desert Road, as the accent.
Crimson #dc143c
shippedCrimson is paired with #455a78 in 14 real palettes, including Codecademy's brand system and Walgreens's brand system, as the accent.
White Smoke #f5f5f5
neutralWhite Smoke is the surface for #455a78: a clean near-white with no warm cast, so the cool hue stays clear instead of drifting muddy.
Real palettes that use #455a78
Tints & shades
Harmonies
Contrast
| #455a78 as text | Ratio | AA | AA large | AAA | Fix |
|---|---|---|---|---|---|
Aaon white | 7.03:1 | pass | pass | pass | Passes AAA — no fix needed. |
Aaon black | 2.99:1 | 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 #455a78 as the background.
Brands using this color
Palettes built around it
mcpConnect your agent — build around #455a78
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 #455a78 and generate a 5-color palette that keeps it as the primary; give me the /palettes/new link
tool url
/palettes/new/455a78-9ca8c4-df5d4e-201f2d-e9f0f1?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