#5176A8

CSS

:root {
  --song-of-the-sea: #5176a8;
  --song-of-the-sea-rgb: 81 118 168;
  --song-of-the-sea-oklch: oklch(0.56 0.089 256.2);
}

.element {
  color: var(--song-of-the-sea);
  background-color: hsl(214 35% 49%);
  border-color: oklch(0.56 0.089 256.2);
}

Tailwind CSS v4

@theme {
  --color-song-of-the-sea: #5176a8;
  --color-song-of-the-sea-50: #e6f7ff;
  --color-song-of-the-sea-100: #d6e9ff;
  --color-song-of-the-sea-200: #bdd6fb;
  --color-song-of-the-sea-300: #9cb9e5;
  --color-song-of-the-sea-400: #7ca1d3;
  --color-song-of-the-sea-500: #5e88c0;
  --color-song-of-the-sea-600: #5073a2;
  --color-song-of-the-sea-700: #405c82;
  --color-song-of-the-sea-800: #2c4461;
  --color-song-of-the-sea-900: #1e2f44;
  --color-song-of-the-sea-950: #0e1b2c;
}

SCSS

$song-of-the-sea: #5176a8;
$song-of-the-sea-rgb: 81, 118, 168;
$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);
}