#4289BB is a mid-toned, cool blue. On the Color Lab it reads clean and engineered. It carries a legible label as a UI accent and sits well as a supporting tone.
Not just a swatch — here's how #4289BB works with other colors. Named schemes with #4289BB in its natural role, and a note on why the supporting colors balance it.
Steel Blue opens this coastal palette with sea-glass and warm sand alongside it, grounded by driftwood grey and a deep-navy anchor.
Steel Blue is the vivid signal in this product UI — on a near-black surface with cool white, a slate grey and a lighter tint of Steel Blue.
Steel Blue plays the worn-leather lead, deepened by saddle brown and an oxblood anchor, softened by aged cream and cooled by a muted forest green.
Steel Blue sits between cream and a deep berry here, softened by a blush accent and grounded by charcoal.
Steel Blue is the single accent in this high-contrast editorial system — set on near-white paper against near-black ink, with a warm grey and a desaturated tint of Steel Blue carrying the quiet middle.
How #4289BB actually behaves in design work — read from its OKLCH lightness, chroma and hue, not just its raw numbers. Ten signals to help you decide where this color earns its place.
Not a swatch to memorise — a color to build with. Here is #4289BB at work across the surfaces designers actually ship.
:root {
--color-base: #4289BB;
--color-base-rgb: 66 137 187;
--color-base-oklch: oklch(60.6% 0.104 242.0);
--color-50: #F3F8FB;
--color-100: #E0ECF5;
--color-200: #C3D9EA;
--color-300: #99BDD7;
--color-400: #71A0C1;
--color-500: #5081A5;
--color-600: #43667F;
--color-700: #344B5B;
--color-800: #25323C;
--color-900: #182025;
--color-on-base: #141310;
}
// tailwind.config.js
colors: {
steel-blue: {
50: '#F3F8FB',
100: '#E0ECF5',
200: '#C3D9EA',
300: '#99BDD7',
400: '#71A0C1',
500: '#5081A5',
600: '#43667F',
700: '#344B5B',
800: '#25323C',
900: '#182025',
},
}
$base: #4289BB; $base-ink: #141310; $base-50: #F3F8FB; $base-100: #E0ECF5; $base-200: #C3D9EA; $base-300: #99BDD7; $base-400: #71A0C1; $base-500: #5081A5; $base-600: #43667F; $base-700: #344B5B; $base-800: #25323C; $base-900: #182025; $base-hover: #356E97; $base-subtle: #CBDBE7;
{
"color": {
"base": {
"value": "#4289BB",
"type": "color"
},
"onBase": {
"value": "#141310",
"type": "color"
},
"scale": {
"50": {
"value": "#F3F8FB",
"type": "color"
},
"100": {
"value": "#E0ECF5",
"type": "color"
},
"200": {
"value": "#C3D9EA",
"type": "color"
},
"300": {
"value": "#99BDD7",
"type": "color"
},
"400": {
"value": "#71A0C1",
"type": "color"
},
"500": {
"value": "#5081A5",
"type": "color"
},
"600": {
"value": "#43667F",
"type": "color"
},
"700": {
"value": "#344B5B",
"type": "color"
},
"800": {
"value": "#25323C",
"type": "color"
},
"900": {
"value": "#182025",
"type": "color"
}
}
}
}