#1C6EBC

CSS

:root {
  --matt-blue: #1c6ebc;
  --matt-blue-rgb: 28 110 188;
  --matt-blue-oklch: oklch(0.532 0.143 251.9);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(209 74% 42%);
  border-color: oklch(0.532 0.143 251.9);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #1c6ebc;
  --color-matt-blue-50: #d9f8ff;
  --color-matt-blue-100: #c7ebff;
  --color-matt-blue-200: #aad8ff;
  --color-matt-blue-300: #83bbff;
  --color-matt-blue-400: #5aa2f0;
  --color-matt-blue-500: #2f88e1;
  --color-matt-blue-600: #2a74be;
  --color-matt-blue-700: #215d99;
  --color-matt-blue-800: #124472;
  --color-matt-blue-900: #0b2f50;
  --color-matt-blue-950: #011b35;
}

SCSS

$matt-blue: #1c6ebc;
$matt-blue-rgb: 28, 110, 188;
$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);
}