#0A1924

CSS

:root {
  --the-count-s-black: #0a1924;
  --the-count-s-black-rgb: 10 25 36;
  --the-count-s-black-oklch: oklch(0.206 0.03 242);
}

.element {
  color: var(--the-count-s-black);
  background-color: hsl(205 57% 9%);
  border-color: oklch(0.206 0.03 242);
}

Tailwind CSS v4

@theme {
  --color-the-count-s-black: #0a1924;
  --color-the-count-s-black-50: #eef6fd;
  --color-the-count-s-black-100: #e0e9f1;
  --color-the-count-s-black-200: #cad6e0;
  --color-the-count-s-black-300: #abbac6;
  --color-the-count-s-black-400: #8fa1af;
  --color-the-count-s-black-500: #758999;
  --color-the-count-s-black-600: #637481;
  --color-the-count-s-black-700: #4f5d67;
  --color-the-count-s-black-800: #39444c;
  --color-the-count-s-black-900: #272f35;
  --color-the-count-s-black-950: #151b20;
}

SCSS

$the-count-s-black: #0a1924;
$the-count-s-black-rgb: 10, 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);
}