#0C1A27

CSS

:root {
  --the-count-s-black: #0c1a27;
  --the-count-s-black-rgb: 12 26 39;
  --the-count-s-black-oklch: oklch(0.212 0.032 247.9);
}

.element {
  color: var(--the-count-s-black);
  background-color: hsl(209 53% 10%);
  border-color: oklch(0.212 0.032 247.9);
}

Tailwind CSS v4

@theme {
  --color-the-count-s-black: #0c1a27;
  --color-the-count-s-black-50: #eef6fe;
  --color-the-count-s-black-100: #e0e9f3;
  --color-the-count-s-black-200: #cad6e2;
  --color-the-count-s-black-300: #abb9c8;
  --color-the-count-s-black-400: #90a1b1;
  --color-the-count-s-black-500: #76899b;
  --color-the-count-s-black-600: #647483;
  --color-the-count-s-black-700: #505c69;
  --color-the-count-s-black-800: #39444d;
  --color-the-count-s-black-900: #272f36;
  --color-the-count-s-black-950: #151b21;
}

SCSS

$the-count-s-black: #0c1a27;
$the-count-s-black-rgb: 12, 26, 39;
$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);
}