#193241

CSS

:root {
  --blue-whale: #193241;
  --blue-whale-rgb: 25 50 65;
  --blue-whale-oklch: oklch(0.304 0.041 236.6);
}

.element {
  color: var(--blue-whale);
  background-color: hsl(203 44% 18%);
  border-color: oklch(0.304 0.041 236.6);
}

Tailwind CSS v4

@theme {
  --color-blue-whale: #193241;
  --color-blue-whale-50: #ebf7ff;
  --color-blue-whale-100: #dceaf4;
  --color-blue-whale-200: #c5d7e4;
  --color-blue-whale-300: #a5bbcb;
  --color-blue-whale-400: #88a3b4;
  --color-blue-whale-500: #6c8b9e;
  --color-blue-whale-600: #5c7586;
  --color-blue-whale-700: #495e6b;
  --color-blue-whale-800: #35454f;
  --color-blue-whale-900: #243037;
  --color-blue-whale-950: #131c22;
}

SCSS

$blue-whale: #193241;
$blue-whale-rgb: 25, 50, 65;
$blue-whale-light: mix(#fff, $blue-whale, 20%);
$blue-whale-dark: mix(#000, $blue-whale, 20%);

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