#426BB3

CSS

:root {
  --song-of-the-sea: #426bb3;
  --song-of-the-sea-rgb: 66 107 179;
  --song-of-the-sea-oklch: oklch(0.533 0.123 260.9);
}

.element {
  color: var(--song-of-the-sea);
  background-color: hsl(218 46% 48%);
  border-color: oklch(0.533 0.123 260.9);
}

Tailwind CSS v4

@theme {
  --color-song-of-the-sea: #426bb3;
  --color-song-of-the-sea-50: #e3f6ff;
  --color-song-of-the-sea-100: #d2e9ff;
  --color-song-of-the-sea-200: #b9d5ff;
  --color-song-of-the-sea-300: #96b7f7;
  --color-song-of-the-sea-400: #749ee7;
  --color-song-of-the-sea-500: #5685d7;
  --color-song-of-the-sea-600: #4970b5;
  --color-song-of-the-sea-700: #3a5a91;
  --color-song-of-the-sea-800: #27426c;
  --color-song-of-the-sea-900: #1a2e4c;
  --color-song-of-the-sea-950: #0b1a32;
}

SCSS

$song-of-the-sea: #426bb3;
$song-of-the-sea-rgb: 66, 107, 179;
$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);
}