#C45154

CSS

:root {
  --autumn-fire: #c45154;
  --autumn-fire-rgb: 196 81 84;
  --autumn-fire-oklch: oklch(0.585 0.148 21.3);
}

.element {
  color: var(--autumn-fire);
  background-color: hsl(358 49% 54%);
  border-color: oklch(0.585 0.148 21.3);
}

Tailwind CSS v4

@theme {
  --color-autumn-fire: #c45154;
  --color-autumn-fire-50: #ffe5e1;
  --color-autumn-fire-100: #ffd5d1;
  --color-autumn-fire-200: #ffbcb6;
  --color-autumn-fire-300: #fa9893;
  --color-autumn-fire-400: #e97777;
  --color-autumn-fire-500: #d6555a;
  --color-autumn-fire-600: #b5494c;
  --color-autumn-fire-700: #913a3d;
  --color-autumn-fire-800: #6c292d;
  --color-autumn-fire-900: #4c1c1e;
  --color-autumn-fire-950: #320b0e;
}

SCSS

$autumn-fire: #c45154;
$autumn-fire-rgb: 196, 81, 84;
$autumn-fire-light: mix(#fff, $autumn-fire, 20%);
$autumn-fire-dark: mix(#000, $autumn-fire, 20%);

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