#B20000

CSS

:root {
  --all-systems-red: #b20000;
  --all-systems-red-rgb: 178 0 0;
  --all-systems-red-oklch: oklch(0.479 0.197 29.2);
}

.element {
  color: var(--all-systems-red);
  background-color: hsl(0 100% 35%);
  border-color: oklch(0.479 0.197 29.2);
}

Tailwind CSS v4

@theme {
  --color-all-systems-red: #b20000;
  --color-all-systems-red-50: #ffe1d3;
  --color-all-systems-red-100: #ffd0c0;
  --color-all-systems-red-200: #ffb4a0;
  --color-all-systems-red-300: #ff8d77;
  --color-all-systems-red-400: #fd6755;
  --color-all-systems-red-500: #ec392c;
  --color-all-systems-red-600: #c73327;
  --color-all-systems-red-700: #a0291f;
  --color-all-systems-red-800: #781b18;
  --color-all-systems-red-900: #55120f;
  --color-all-systems-red-950: #390303;
}

SCSS

$all-systems-red: #b20000;
$all-systems-red-rgb: 178, 0, 0;
$all-systems-red-light: mix(#fff, $all-systems-red, 20%);
$all-systems-red-dark: mix(#000, $all-systems-red, 20%);

.element {
  color: $all-systems-red;
  box-shadow: 0 0 0 2px rgba($all-systems-red, 0.35);
}