#398167

CSS

:root {
  --shadows-of-time: #398167;
  --shadows-of-time-rgb: 57 129 103;
  --shadows-of-time-oklch: oklch(0.549 0.084 167);
}

.element {
  color: var(--shadows-of-time);
  background-color: hsl(158 39% 36%);
  border-color: oklch(0.549 0.084 167);
}

Tailwind CSS v4

@theme {
  --color-shadows-of-time: #398167;
  --color-shadows-of-time-50: #dffdf1;
  --color-shadows-of-time-100: #cef1e3;
  --color-shadows-of-time-200: #b2e0ce;
  --color-shadows-of-time-300: #8dc6b0;
  --color-shadows-of-time-400: #6baf94;
  --color-shadows-of-time-500: #47987a;
  --color-shadows-of-time-600: #3d8068;
  --color-shadows-of-time-700: #316753;
  --color-shadows-of-time-800: #234c3b;
  --color-shadows-of-time-900: #173429;
  --color-shadows-of-time-950: #082016;
}

SCSS

$shadows-of-time: #398167;
$shadows-of-time-rgb: 57, 129, 103;
$shadows-of-time-light: mix(#fff, $shadows-of-time, 20%);
$shadows-of-time-dark: mix(#000, $shadows-of-time, 20%);

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