#136CC7

CSS

:root {
  --matt-blue: #136cc7;
  --matt-blue-rgb: 19 108 199;
  --matt-blue-oklch: oklch(0.534 0.162 254.2);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(210 83% 43%);
  border-color: oklch(0.534 0.162 254.2);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #136cc7;
  --color-matt-blue-50: #d8f8ff;
  --color-matt-blue-100: #c5ebff;
  --color-matt-blue-200: #a7d7ff;
  --color-matt-blue-300: #7fbaff;
  --color-matt-blue-400: #55a1fb;
  --color-matt-blue-500: #2686ed;
  --color-matt-blue-600: #2372c8;
  --color-matt-blue-700: #1c5ba1;
  --color-matt-blue-800: #0c4378;
  --color-matt-blue-900: #082e55;
  --color-matt-blue-950: #001b39;
}

SCSS

$matt-blue: #136cc7;
$matt-blue-rgb: 19, 108, 199;
$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);
}