#386CB7

CSS

:root {
  --matt-blue: #386cb7;
  --matt-blue-rgb: 56 108 183;
  --matt-blue-oklch: oklch(0.533 0.131 257.8);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(215 53% 47%);
  border-color: oklch(0.533 0.131 257.8);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #386cb7;
  --color-matt-blue-50: #e0f7ff;
  --color-matt-blue-100: #cfeaff;
  --color-matt-blue-200: #b4d6ff;
  --color-matt-blue-300: #90b9fa;
  --color-matt-blue-400: #6ca0eb;
  --color-matt-blue-500: #4b86db;
  --color-matt-blue-600: #4071b9;
  --color-matt-blue-700: #335b95;
  --color-matt-blue-800: #21436f;
  --color-matt-blue-900: #162e4e;
  --color-matt-blue-950: #071b34;
}

SCSS

$matt-blue: #386cb7;
$matt-blue-rgb: 56, 108, 183;
$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);
}