#1E6BC8

CSS

:root {
  --matt-blue: #1e6bc8;
  --matt-blue-rgb: 30 107 200;
  --matt-blue-oklch: oklch(0.534 0.162 256.1);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(213 74% 45%);
  border-color: oklch(0.534 0.162 256.1);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #1e6bc8;
  --color-matt-blue-50: #d9f7ff;
  --color-matt-blue-100: #c7eaff;
  --color-matt-blue-200: #a9d6ff;
  --color-matt-blue-300: #82b9ff;
  --color-matt-blue-400: #599ffc;
  --color-matt-blue-500: #3085ee;
  --color-matt-blue-600: #2a70c9;
  --color-matt-blue-700: #215aa2;
  --color-matt-blue-800: #114278;
  --color-matt-blue-900: #0b2e55;
  --color-matt-blue-950: #001a39;
}

SCSS

$matt-blue: #1e6bc8;
$matt-blue-rgb: 30, 107, 200;
$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);
}