#3F6DAC

CSS

:root {
  --song-of-the-sea: #3f6dac;
  --song-of-the-sea-rgb: 63 109 172;
  --song-of-the-sea-oklch: oklch(0.532 0.112 256.7);
}

.element {
  color: var(--song-of-the-sea);
  background-color: hsl(215 46% 46%);
  border-color: oklch(0.532 0.112 256.7);
}

Tailwind CSS v4

@theme {
  --color-song-of-the-sea: #3f6dac;
  --color-song-of-the-sea-50: #e2f7ff;
  --color-song-of-the-sea-100: #d2eaff;
  --color-song-of-the-sea-200: #b8d6ff;
  --color-song-of-the-sea-300: #95b9f1;
  --color-song-of-the-sea-400: #73a0e0;
  --color-song-of-the-sea-500: #5387cf;
  --color-song-of-the-sea-600: #4773af;
  --color-song-of-the-sea-700: #385c8c;
  --color-song-of-the-sea-800: #264368;
  --color-song-of-the-sea-900: #192f49;
  --color-song-of-the-sea-950: #0a1b30;
}

SCSS

$song-of-the-sea: #3f6dac;
$song-of-the-sea-rgb: 63, 109, 172;
$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);
}