#A9978F

CSS

:root {
  --cortex: #a9978f;
  --cortex-rgb: 169 151 143;
  --cortex-oklch: oklch(0.69 0.024 45.5);
}

.element {
  color: var(--cortex);
  background-color: hsl(18 13% 61%);
  border-color: oklch(0.69 0.024 45.5);
}

Tailwind CSS v4

@theme {
  --color-cortex: #a9978f;
  --color-cortex-50: #fbf3ef;
  --color-cortex-100: #efe6e1;
  --color-cortex-200: #ded1cb;
  --color-cortex-300: #c3b4ad;
  --color-cortex-400: #ab9a93;
  --color-cortex-500: #958279;
  --color-cortex-600: #7e6e66;
  --color-cortex-700: #655852;
  --color-cortex-800: #4a403c;
  --color-cortex-900: #332c29;
  --color-cortex-950: #1f1917;
}

SCSS

$cortex: #a9978f;
$cortex-rgb: 169, 151, 143;
$cortex-light: mix(#fff, $cortex, 20%);
$cortex-dark: mix(#000, $cortex, 20%);

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