#00475A

CSS

:root {
  --raging-thunderstorm: #00475a;
  --raging-thunderstorm-rgb: 0 71 90;
  --raging-thunderstorm-oklch: oklch(0.369 0.069 223.2);
}

.element {
  color: var(--raging-thunderstorm);
  background-color: hsl(193 100% 18%);
  border-color: oklch(0.369 0.069 223.2);
}

Tailwind CSS v4

@theme {
  --color-raging-thunderstorm: #00475a;
  --color-raging-thunderstorm-50: #e1faff;
  --color-raging-thunderstorm-100: #d1edfa;
  --color-raging-thunderstorm-200: #b6dbeb;
  --color-raging-thunderstorm-300: #92bfd2;
  --color-raging-thunderstorm-400: #70a8bc;
  --color-raging-thunderstorm-500: #4e90a8;
  --color-raging-thunderstorm-600: #437a8e;
  --color-raging-thunderstorm-700: #356272;
  --color-raging-thunderstorm-800: #254853;
  --color-raging-thunderstorm-900: #19323a;
  --color-raging-thunderstorm-950: #091e24;
}

SCSS

$raging-thunderstorm: #00475a;
$raging-thunderstorm-rgb: 0, 71, 90;
$raging-thunderstorm-light: mix(#fff, $raging-thunderstorm, 20%);
$raging-thunderstorm-dark: mix(#000, $raging-thunderstorm, 20%);

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