#51717D

CSS

:root {
  --winter-storm: #51717d;
  --winter-storm-rgb: 81 113 125;
  --winter-storm-oklch: oklch(0.529 0.041 223.1);
}

.element {
  color: var(--winter-storm);
  background-color: hsl(196 21% 40%);
  border-color: oklch(0.529 0.041 223.1);
}

Tailwind CSS v4

@theme {
  --color-winter-storm: #51717d;
  --color-winter-storm-50: #e9f8fe;
  --color-winter-storm-100: #daebf2;
  --color-winter-storm-200: #c2d8e2;
  --color-winter-storm-300: #a2bcc8;
  --color-winter-storm-400: #85a4b0;
  --color-winter-storm-500: #688d9a;
  --color-winter-storm-600: #597782;
  --color-winter-storm-700: #475f69;
  --color-winter-storm-800: #33464d;
  --color-winter-storm-900: #223035;
  --color-winter-storm-950: #111d20;
}

SCSS

$winter-storm: #51717d;
$winter-storm-rgb: 81, 113, 125;
$winter-storm-light: mix(#fff, $winter-storm, 20%);
$winter-storm-dark: mix(#000, $winter-storm, 20%);

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