#00484F

CSS

:root {
  --rich-black: #00484f;
  --rich-black-rgb: 0 72 79;
  --rich-black-oklch: oklch(0.367 0.063 205.9);
}

.element {
  color: var(--rich-black);
  background-color: hsl(185 100% 15%);
  border-color: oklch(0.367 0.063 205.9);
}

Tailwind CSS v4

@theme {
  --color-rich-black: #00484f;
  --color-rich-black-50: #e2fbff;
  --color-rich-black-100: #d1eef3;
  --color-rich-black-200: #b6dce2;
  --color-rich-black-300: #92c1c8;
  --color-rich-black-400: #71a9b1;
  --color-rich-black-500: #50929b;
  --color-rich-black-600: #447c83;
  --color-rich-black-700: #366369;
  --color-rich-black-800: #26494c;
  --color-rich-black-900: #193235;
  --color-rich-black-950: #0a1e20;
}

SCSS

$rich-black: #00484f;
$rich-black-rgb: 0, 72, 79;
$rich-black-light: mix(#fff, $rich-black, 20%);
$rich-black-dark: mix(#000, $rich-black, 20%);

.element {
  color: $rich-black;
  box-shadow: 0 0 0 2px rgba($rich-black, 0.35);
}