#256CC4

CSS

:root {
  --matt-blue: #256cc4;
  --matt-blue-rgb: 37 108 196;
  --matt-blue-oklch: oklch(0.535 0.154 256);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(213 68% 46%);
  border-color: oklch(0.535 0.154 256);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #256cc4;
  --color-matt-blue-50: #daf7ff;
  --color-matt-blue-100: #c8eaff;
  --color-matt-blue-200: #abd6ff;
  --color-matt-blue-300: #85b9ff;
  --color-matt-blue-400: #5da0f7;
  --color-matt-blue-500: #3685e9;
  --color-matt-blue-600: #2f71c5;
  --color-matt-blue-700: #265a9e;
  --color-matt-blue-800: #154376;
  --color-matt-blue-900: #0d2e53;
  --color-matt-blue-950: #021a38;
}

SCSS

$matt-blue: #256cc4;
$matt-blue-rgb: 37, 108, 196;
$matt-blue-light: mix(#fff, $matt-blue, 20%);
$matt-blue-dark: mix(#000, $matt-blue, 20%);

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