#0099B3

CSS

:root {
  --munsell-blue: #0099b3;
  --munsell-blue-rgb: 0 153 179;
  --munsell-blue-oklch: oklch(0.629 0.111 215.4);
}

.element {
  color: var(--munsell-blue);
  background-color: hsl(189 100% 35%);
  border-color: oklch(0.629 0.111 215.4);
}

Tailwind CSS v4

@theme {
  --color-munsell-blue: #0099b3;
  --color-munsell-blue-50: #d3feff;
  --color-munsell-blue-100: #bff2ff;
  --color-munsell-blue-200: #9de1f4;
  --color-munsell-blue-300: #70c6dd;
  --color-munsell-blue-400: #3dafc8;
  --color-munsell-blue-500: #0098b4;
  --color-munsell-blue-600: #008098;
  --color-munsell-blue-700: #00677a;
  --color-munsell-blue-800: #004c59;
  --color-munsell-blue-900: #00353f;
  --color-munsell-blue-950: #002028;
}

SCSS

$munsell-blue: #0099b3;
$munsell-blue-rgb: 0, 153, 179;
$munsell-blue-light: mix(#fff, $munsell-blue, 20%);
$munsell-blue-dark: mix(#000, $munsell-blue, 20%);

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