#657A7A

CSS

:root {
  --blue-blood: #657a7a;
  --blue-blood-rgb: 101 122 122;
  --blue-blood-oklch: oklch(0.563 0.025 196.5);
}

.element {
  color: var(--blue-blood);
  background-color: hsl(180 9% 44%);
  border-color: oklch(0.563 0.025 196.5);
}

Tailwind CSS v4

@theme {
  --color-blue-blood: #657a7a;
  --color-blue-blood-50: #eef7f8;
  --color-blue-blood-100: #dfebeb;
  --color-blue-blood-200: #c9d8d8;
  --color-blue-blood-300: #aabbbc;
  --color-blue-blood-400: #8ea3a3;
  --color-blue-blood-500: #748c8c;
  --color-blue-blood-600: #627676;
  --color-blue-blood-700: #4e5e5e;
  --color-blue-blood-800: #394545;
  --color-blue-blood-900: #273030;
  --color-blue-blood-950: #151c1c;
}

SCSS

$blue-blood: #657a7a;
$blue-blood-rgb: 101, 122, 122;
$blue-blood-light: mix(#fff, $blue-blood, 20%);
$blue-blood-dark: mix(#000, $blue-blood, 20%);

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