#E9F5EB

CSS

:root {
  --polar: #e9f5eb;
  --polar-rgb: 233 245 235;
  --polar-oklch: oklch(0.958 0.018 150.6);
}

.element {
  color: var(--polar);
  background-color: hsl(130 38% 94%);
  border-color: oklch(0.958 0.018 150.6);
}

Tailwind CSS v4

@theme {
  --color-polar: #e9f5eb;
  --color-polar-50: #f1f7f3;
  --color-polar-100: #e4eae5;
  --color-polar-200: #cfd7d0;
  --color-polar-300: #b1bab3;
  --color-polar-400: #97a299;
  --color-polar-500: #7e8a80;
  --color-polar-600: #6b756c;
  --color-polar-700: #555d57;
  --color-polar-800: #3e443f;
  --color-polar-900: #2b2f2b;
  --color-polar-950: #181c19;
}

SCSS

$polar: #e9f5eb;
$polar-rgb: 233, 245, 235;
$polar-light: mix(#fff, $polar, 20%);
$polar-dark: mix(#000, $polar, 20%);

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