#22313D

CSS

:root {
  --blue-whale: #22313d;
  --blue-whale-rgb: 34 49 61;
  --blue-whale-oklch: oklch(0.305 0.03 243);
}

.element {
  color: var(--blue-whale);
  background-color: hsl(207 28% 19%);
  border-color: oklch(0.305 0.03 243);
}

Tailwind CSS v4

@theme {
  --color-blue-whale: #22313d;
  --color-blue-whale-50: #eef6fd;
  --color-blue-whale-100: #e0e9f1;
  --color-blue-whale-200: #cad6e0;
  --color-blue-whale-300: #abb9c6;
  --color-blue-whale-400: #90a1af;
  --color-blue-whale-500: #768999;
  --color-blue-whale-600: #647481;
  --color-blue-whale-700: #505d67;
  --color-blue-whale-800: #3a444c;
  --color-blue-whale-900: #272f35;
  --color-blue-whale-950: #151b20;
}

SCSS

$blue-whale: #22313d;
$blue-whale-rgb: 34, 49, 61;
$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);
}