#427479

CSS

:root {
  --ocean-slumber: #427479;
  --ocean-slumber-rgb: 66 116 121;
  --ocean-slumber-oklch: oklch(0.526 0.054 203.9);
}

.element {
  color: var(--ocean-slumber);
  background-color: hsl(185 29% 37%);
  border-color: oklch(0.526 0.054 203.9);
}

Tailwind CSS v4

@theme {
  --color-ocean-slumber: #427479;
  --color-ocean-slumber-50: #e4fafd;
  --color-ocean-slumber-100: #d4eef1;
  --color-ocean-slumber-200: #badbe0;
  --color-ocean-slumber-300: #97c0c5;
  --color-ocean-slumber-400: #78a8ad;
  --color-ocean-slumber-500: #599197;
  --color-ocean-slumber-600: #4c7b7f;
  --color-ocean-slumber-700: #3c6266;
  --color-ocean-slumber-800: #2b484a;
  --color-ocean-slumber-900: #1d3234;
  --color-ocean-slumber-950: #0d1e1f;
}

SCSS

$ocean-slumber: #427479;
$ocean-slumber-rgb: 66, 116, 121;
$ocean-slumber-light: mix(#fff, $ocean-slumber, 20%);
$ocean-slumber-dark: mix(#000, $ocean-slumber, 20%);

.element {
  color: $ocean-slumber;
  box-shadow: 0 0 0 2px rgba($ocean-slumber, 0.35);
}