#182A3C

CSS

:root {
  --the-count-s-black: #182a3c;
  --the-count-s-black-rgb: 24 42 60;
  --the-count-s-black-oklch: oklch(0.279 0.041 249.5);
}

.element {
  color: var(--the-count-s-black);
  background-color: hsl(210 43% 16%);
  border-color: oklch(0.279 0.041 249.5);
}

Tailwind CSS v4

@theme {
  --color-the-count-s-black: #182a3c;
  --color-the-count-s-black-50: #edf6ff;
  --color-the-count-s-black-100: #dee9f6;
  --color-the-count-s-black-200: #c8d6e6;
  --color-the-count-s-black-300: #a9b9cc;
  --color-the-count-s-black-400: #8ca1b6;
  --color-the-count-s-black-500: #7289a1;
  --color-the-count-s-black-600: #607488;
  --color-the-count-s-black-700: #4d5d6d;
  --color-the-count-s-black-800: #374450;
  --color-the-count-s-black-900: #262f38;
  --color-the-count-s-black-950: #141b22;
}

SCSS

$the-count-s-black: #182a3c;
$the-count-s-black-rgb: 24, 42, 60;
$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);
}