#476DA3

CSS

:root {
  --song-of-the-sea: #476da3;
  --song-of-the-sea-rgb: 71 109 163;
  --song-of-the-sea-oklch: oklch(0.531 0.096 257.3);
}

.element {
  color: var(--song-of-the-sea);
  background-color: hsl(215 39% 46%);
  border-color: oklch(0.531 0.096 257.3);
}

Tailwind CSS v4

@theme {
  --color-song-of-the-sea: #476da3;
  --color-song-of-the-sea-50: #e5f6ff;
  --color-song-of-the-sea-100: #d5e9ff;
  --color-song-of-the-sea-200: #bcd6fe;
  --color-song-of-the-sea-300: #9ab9e9;
  --color-song-of-the-sea-400: #7aa0d7;
  --color-song-of-the-sea-500: #5c87c5;
  --color-song-of-the-sea-600: #4e73a6;
  --color-song-of-the-sea-700: #3e5c86;
  --color-song-of-the-sea-800: #2b4363;
  --color-song-of-the-sea-900: #1d2f46;
  --color-song-of-the-sea-950: #0d1b2d;
}

SCSS

$song-of-the-sea: #476da3;
$song-of-the-sea-rgb: 71, 109, 163;
$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);
}