#4059E3

CSS

:root {
  --warm-blue: #4059e3;
  --warm-blue-rgb: 64 89 227;
  --warm-blue-oklch: oklch(0.531 0.21 269.8);
}

.element {
  color: var(--warm-blue);
  background-color: hsl(231 74% 57%);
  border-color: oklch(0.531 0.21 269.8);
}

Tailwind CSS v4

@theme {
  --color-warm-blue: #4059e3;
  --color-warm-blue-50: #dff3ff;
  --color-warm-blue-100: #cfe4ff;
  --color-warm-blue-200: #b4ceff;
  --color-warm-blue-300: #92aeff;
  --color-warm-blue-400: #6f92ff;
  --color-warm-blue-500: #5372ff;
  --color-warm-blue-600: #4661e4;
  --color-warm-blue-700: #384eb7;
  --color-warm-blue-800: #23398a;
  --color-warm-blue-900: #172762;
  --color-warm-blue-950: #091443;
}

SCSS

$warm-blue: #4059e3;
$warm-blue-rgb: 64, 89, 227;
$warm-blue-light: mix(#fff, $warm-blue, 20%);
$warm-blue-dark: mix(#000, $warm-blue, 20%);

.element {
  color: $warm-blue;
  box-shadow: 0 0 0 2px rgba($warm-blue, 0.35);
}