#C34D54

CSS

:root {
  --autumn-fire: #c34d54;
  --autumn-fire-rgb: 195 77 84;
  --autumn-fire-oklch: oklch(0.578 0.151 19.6);
}

.element {
  color: var(--autumn-fire);
  background-color: hsl(356 50% 53%);
  border-color: oklch(0.578 0.151 19.6);
}

Tailwind CSS v4

@theme {
  --color-autumn-fire: #c34d54;
  --color-autumn-fire-50: #ffe5e2;
  --color-autumn-fire-100: #ffd5d2;
  --color-autumn-fire-200: #ffbbb8;
  --color-autumn-fire-300: #fb9795;
  --color-autumn-fire-400: #ea7679;
  --color-autumn-fire-500: #d8535c;
  --color-autumn-fire-600: #b6484e;
  --color-autumn-fire-700: #93393e;
  --color-autumn-fire-800: #6d282e;
  --color-autumn-fire-900: #4d1b1f;
  --color-autumn-fire-950: #320b0f;
}

SCSS

$autumn-fire: #c34d54;
$autumn-fire-rgb: 195, 77, 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);
}