#0C1925

CSS

:root {
  --the-count-s-black: #0c1925;
  --the-count-s-black-rgb: 12 25 37;
  --the-count-s-black-oklch: oklch(0.208 0.03 247.6);
}

.element {
  color: var(--the-count-s-black);
  background-color: hsl(209 51% 10%);
  border-color: oklch(0.208 0.03 247.6);
}

Tailwind CSS v4

@theme {
  --color-the-count-s-black: #0c1925;
  --color-the-count-s-black-50: #eff6fe;
  --color-the-count-s-black-100: #e0e9f2;
  --color-the-count-s-black-200: #cbd6e1;
  --color-the-count-s-black-300: #acb9c7;
  --color-the-count-s-black-400: #91a0b0;
  --color-the-count-s-black-500: #77889a;
  --color-the-count-s-black-600: #657382;
  --color-the-count-s-black-700: #505c68;
  --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: #0c1925;
$the-count-s-black-rgb: 12, 25, 37;
$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);
}