#033B6D

CSS

:root {
  --tardis-blue: #033b6d;
  --tardis-blue-rgb: 3 59 109;
  --tardis-blue-oklch: oklch(0.35 0.102 251.9);
}

.element {
  color: var(--tardis-blue);
  background-color: hsl(208 95% 22%);
  border-color: oklch(0.35 0.102 251.9);
}

Tailwind CSS v4

@theme {
  --color-tardis-blue: #033b6d;
  --color-tardis-blue-50: #e2f7ff;
  --color-tardis-blue-100: #d1ebff;
  --color-tardis-blue-200: #b7d7ff;
  --color-tardis-blue-300: #93bbeb;
  --color-tardis-blue-400: #71a2d9;
  --color-tardis-blue-500: #518ac7;
  --color-tardis-blue-600: #4574a8;
  --color-tardis-blue-700: #375d87;
  --color-tardis-blue-800: #254564;
  --color-tardis-blue-900: #192f46;
  --color-tardis-blue-950: #091c2e;
}

SCSS

$tardis-blue: #033b6d;
$tardis-blue-rgb: 3, 59, 109;
$tardis-blue-light: mix(#fff, $tardis-blue, 20%);
$tardis-blue-dark: mix(#000, $tardis-blue, 20%);

.element {
  color: $tardis-blue;
  box-shadow: 0 0 0 2px rgba($tardis-blue, 0.35);
}