#0F1826

CSS

:root {
  --the-count-s-black: #0f1826;
  --the-count-s-black-rgb: 15 24 38;
  --the-count-s-black-oklch: oklch(0.208 0.031 259);
}

.element {
  color: var(--the-count-s-black);
  background-color: hsl(217 43% 10%);
  border-color: oklch(0.208 0.031 259);
}

Tailwind CSS v4

@theme {
  --color-the-count-s-black: #0f1826;
  --color-the-count-s-black-50: #f0f5fe;
  --color-the-count-s-black-100: #e2e8f3;
  --color-the-count-s-black-200: #cdd5e2;
  --color-the-count-s-black-300: #afb8c8;
  --color-the-count-s-black-400: #949fb1;
  --color-the-count-s-black-500: #7a879b;
  --color-the-count-s-black-600: #677283;
  --color-the-count-s-black-700: #535b69;
  --color-the-count-s-black-800: #3c434d;
  --color-the-count-s-black-900: #292e36;
  --color-the-count-s-black-950: #171b21;
}

SCSS

$the-count-s-black: #0f1826;
$the-count-s-black-rgb: 15, 24, 38;
$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);
}