#0C1924

CSS

:root {
  --the-count-s-black: #0c1924;
  --the-count-s-black-rgb: 12 25 36;
  --the-count-s-black-oklch: oklch(0.207 0.029 245.3);
}

.element {
  color: var(--the-count-s-black);
  background-color: hsl(208 50% 9%);
  border-color: oklch(0.207 0.029 245.3);
}

Tailwind CSS v4

@theme {
  --color-the-count-s-black: #0c1924;
  --color-the-count-s-black-50: #eff6fd;
  --color-the-count-s-black-100: #e1e9f1;
  --color-the-count-s-black-200: #cbd6e0;
  --color-the-count-s-black-300: #acb9c6;
  --color-the-count-s-black-400: #91a1af;
  --color-the-count-s-black-500: #778998;
  --color-the-count-s-black-600: #657481;
  --color-the-count-s-black-700: #505c67;
  --color-the-count-s-black-800: #3a444c;
  --color-the-count-s-black-900: #282f35;
  --color-the-count-s-black-950: #161b20;
}

SCSS

$the-count-s-black: #0c1924;
$the-count-s-black-rgb: 12, 25, 36;
$the-count-s-black-light: mix(#fff, $the-count-s-black, 20%);
$the-count-s-black-dark: mix(#000, $the-count-s-black, 20%);

.element {
  color: $the-count-s-black;
  box-shadow: 0 0 0 2px rgba($the-count-s-black, 0.35);
}