#37816A

CSS

:root {
  --shadows-of-time: #37816a;
  --shadows-of-time-rgb: 55 129 106;
  --shadows-of-time-oklch: oklch(0.55 0.083 170);
}

.element {
  color: var(--shadows-of-time);
  background-color: hsl(161 40% 36%);
  border-color: oklch(0.55 0.083 170);
}

Tailwind CSS v4

@theme {
  --color-shadows-of-time: #37816a;
  --color-shadows-of-time-50: #dffdf2;
  --color-shadows-of-time-100: #cdf1e5;
  --color-shadows-of-time-200: #b1e0d0;
  --color-shadows-of-time-300: #8cc6b3;
  --color-shadows-of-time-400: #6aaf97;
  --color-shadows-of-time-500: #45987e;
  --color-shadows-of-time-600: #3c806b;
  --color-shadows-of-time-700: #2f6755;
  --color-shadows-of-time-800: #224c3d;
  --color-shadows-of-time-900: #17342a;
  --color-shadows-of-time-950: #072017;
}

SCSS

$shadows-of-time: #37816a;
$shadows-of-time-rgb: 55, 129, 106;
$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);
}