#5175AE

CSS

:root {
  --song-of-the-sea: #5175ae;
  --song-of-the-sea-rgb: 81 117 174;
  --song-of-the-sea-oklch: oklch(0.561 0.098 259.3);
}

.element {
  color: var(--song-of-the-sea);
  background-color: hsl(217 36% 50%);
  border-color: oklch(0.561 0.098 259.3);
}

Tailwind CSS v4

@theme {
  --color-song-of-the-sea: #5175ae;
  --color-song-of-the-sea-50: #e6f6ff;
  --color-song-of-the-sea-100: #d6e9ff;
  --color-song-of-the-sea-200: #bdd5ff;
  --color-song-of-the-sea-300: #9bb8ea;
  --color-song-of-the-sea-400: #7ba0d9;
  --color-song-of-the-sea-500: #5e87c7;
  --color-song-of-the-sea-600: #5072a8;
  --color-song-of-the-sea-700: #405b87;
  --color-song-of-the-sea-800: #2c4364;
  --color-song-of-the-sea-900: #1e2e46;
  --color-song-of-the-sea-950: #0e1b2e;
}

SCSS

$song-of-the-sea: #5175ae;
$song-of-the-sea-rgb: 81, 117, 174;
$song-of-the-sea-light: mix(#fff, $song-of-the-sea, 20%);
$song-of-the-sea-dark: mix(#000, $song-of-the-sea, 20%);

.element {
  color: $song-of-the-sea;
  box-shadow: 0 0 0 2px rgba($song-of-the-sea, 0.35);
}