#4183EE is a mid-toned, cool indigo. On the Color Lab it reads clean and engineered, bold and ownable. It carries a legible label as a UI accent and sits well as a supporting tone.
Not just a swatch — here's how #4183EE works with other colors. Named schemes with #4183EE in its natural role, and a note on why the supporting colors balance it.
Signal Blue opens this coastal palette with sea-glass and warm sand alongside it, grounded by driftwood grey and a deep-navy anchor.
Signal Blue keeps this Nordic scheme quiet — cool greys and a soft white around it, a muted-blue support and a charcoal anchor.
Signal 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 Signal Blue.
Signal 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 Signal Blue carrying the quiet middle.
Signal Blue anchors this café scheme as the warm mid-tone, lifted by latte cream and a muted sage accent and grounded by espresso brown and a warm charcoal.
How #4183EE 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 #4183EE at work across the surfaces designers actually ship.
:root {
--color-base: #4183EE;
--color-base-rgb: 65 131 238;
--color-base-oklch: oklch(62.2% 0.175 259.6);
--color-50: #F0F6FE;
--color-100: #D8E6FD;
--color-200: #B4CEF8;
--color-300: #81ABEE;
--color-400: #5389DF;
--color-500: #3069C4;
--color-600: #2D5595;
--color-700: #253F69;
--color-800: #1C2C45;
--color-900: #131C2A;
--color-on-base: #141310;
}
// tailwind.config.js
colors: {
signal-blue: {
50: '#F0F6FE',
100: '#D8E6FD',
200: '#B4CEF8',
300: '#81ABEE',
400: '#5389DF',
500: '#3069C4',
600: '#2D5595',
700: '#253F69',
800: '#1C2C45',
900: '#131C2A',
},
}
$base: #4183EE; $base-ink: #141310; $base-50: #F0F6FE; $base-100: #D8E6FD; $base-200: #B4CEF8; $base-300: #81ABEE; $base-400: #5389DF; $base-500: #3069C4; $base-600: #2D5595; $base-700: #253F69; $base-800: #1C2C45; $base-900: #131C2A; $base-hover: #1361DD; $base-subtle: #CCDBF4;
{
"color": {
"base": {
"value": "#4183EE",
"type": "color"
},
"onBase": {
"value": "#141310",
"type": "color"
},
"scale": {
"50": {
"value": "#F0F6FE",
"type": "color"
},
"100": {
"value": "#D8E6FD",
"type": "color"
},
"200": {
"value": "#B4CEF8",
"type": "color"
},
"300": {
"value": "#81ABEE",
"type": "color"
},
"400": {
"value": "#5389DF",
"type": "color"
},
"500": {
"value": "#3069C4",
"type": "color"
},
"600": {
"value": "#2D5595",
"type": "color"
},
"700": {
"value": "#253F69",
"type": "color"
},
"800": {
"value": "#1C2C45",
"type": "color"
},
"900": {
"value": "#131C2A",
"type": "color"
}
}
}
}