#3B6EAB

CSS

:root {
  --matt-blue: #3b6eab;
  --matt-blue-rgb: 59 110 171;
  --matt-blue-oklch: oklch(0.532 0.111 254.2);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(213 49% 45%);
  border-color: oklch(0.532 0.111 254.2);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #3b6eab;
  --color-matt-blue-50: #e1f7ff;
  --color-matt-blue-100: #d0eaff;
  --color-matt-blue-200: #b6d7ff;
  --color-matt-blue-300: #92baf0;
  --color-matt-blue-400: #6fa1df;
  --color-matt-blue-500: #4f88ce;
  --color-matt-blue-600: #4374ae;
  --color-matt-blue-700: #355c8c;
  --color-matt-blue-800: #244468;
  --color-matt-blue-900: #182f49;
  --color-matt-blue-950: #081b30;
}

SCSS

$matt-blue: #3b6eab;
$matt-blue-rgb: 59, 110, 171;
$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);
}