#00484A

CSS

:root {
  --rich-black: #00484a;
  --rich-black-rgb: 0 72 74;
  --rich-black-oklch: oklch(0.365 0.062 198);
}

.element {
  color: var(--rich-black);
  background-color: hsl(182 100% 15%);
  border-color: oklch(0.365 0.062 198);
}

Tailwind CSS v4

@theme {
  --color-rich-black: #00484a;
  --color-rich-black-50: #e2fbfc;
  --color-rich-black-100: #d1eff0;
  --color-rich-black-200: #b6dddf;
  --color-rich-black-300: #92c2c4;
  --color-rich-black-400: #72aaac;
  --color-rich-black-500: #509395;
  --color-rich-black-600: #457c7e;
  --color-rich-black-700: #376465;
  --color-rich-black-800: #274949;
  --color-rich-black-900: #1a3333;
  --color-rich-black-950: #0a1e1f;
}

SCSS

$rich-black: #00484a;
$rich-black-rgb: 0, 72, 74;
$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);
}