#406BB5

CSS

:root {
  --song-of-the-sea: #406bb5;
  --song-of-the-sea-rgb: 64 107 181;
  --song-of-the-sea-oklch: oklch(0.533 0.126 260.6);
}

.element {
  color: var(--song-of-the-sea);
  background-color: hsl(218 48% 48%);
  border-color: oklch(0.533 0.126 260.6);
}

Tailwind CSS v4

@theme {
  --color-song-of-the-sea: #406bb5;
  --color-song-of-the-sea-50: #e2f6ff;
  --color-song-of-the-sea-100: #d2e9ff;
  --color-song-of-the-sea-200: #b8d5ff;
  --color-song-of-the-sea-300: #95b7f8;
  --color-song-of-the-sea-400: #739ee9;
  --color-song-of-the-sea-500: #5385d9;
  --color-song-of-the-sea-600: #4770b7;
  --color-song-of-the-sea-700: #395a93;
  --color-song-of-the-sea-800: #26426d;
  --color-song-of-the-sea-900: #192e4d;
  --color-song-of-the-sea-950: #0a1a33;
}

SCSS

$song-of-the-sea: #406bb5;
$song-of-the-sea-rgb: 64, 107, 181;
$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);
}