Cold and Dark

CSS

:root {
  --cold-and-dark: #154250;
  --cold-and-dark-rgb: 21 66 80;
  --cold-and-dark-oklch: oklch(0.355 0.054 222.1);
}

.element {
  color: var(--cold-and-dark);
  background-color: hsl(194 58% 20%);
  border-color: oklch(0.355 0.054 222.1);
}

Tailwind CSS v4

@theme {
  --color-cold-and-dark: #154250;
  --color-cold-and-dark-50: #e6f9ff;
  --color-cold-and-dark-100: #d6ecf5;
  --color-cold-and-dark-200: #bddae6;
  --color-cold-and-dark-300: #9bbecc;
  --color-cold-and-dark-400: #7ca6b5;
  --color-cold-and-dark-500: #5d8fa0;
  --color-cold-and-dark-600: #4f7987;
  --color-cold-and-dark-700: #3f616c;
  --color-cold-and-dark-800: #2d474f;
  --color-cold-and-dark-900: #1e3137;
  --color-cold-and-dark-950: #0e1d22;
}

SCSS

$cold-and-dark: #154250;
$cold-and-dark-rgb: 21, 66, 80;
$cold-and-dark-light: mix(#fff, $cold-and-dark, 20%);
$cold-and-dark-dark: mix(#000, $cold-and-dark, 20%);

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