Blue Grey

CSS

:root {
  --blue-grey: #758da3;
  --blue-grey-rgb: 117 141 163;
  --blue-grey-oklch: oklch(0.633 0.043 246.2);
}

.element {
  color: var(--blue-grey);
  background-color: hsl(209 20% 55%);
  border-color: oklch(0.633 0.043 246.2);
}

Tailwind CSS v4

@theme {
  --color-blue-grey: #758da3;
  --color-blue-grey-50: #ecf7ff;
  --color-blue-grey-100: #ddeaf6;
  --color-blue-grey-200: #c6d6e6;
  --color-blue-grey-300: #a7bacd;
  --color-blue-grey-400: #8aa1b7;
  --color-blue-grey-500: #6f89a2;
  --color-blue-grey-600: #5e7489;
  --color-blue-grey-700: #4b5d6d;
  --color-blue-grey-800: #364450;
  --color-blue-grey-900: #252f38;
  --color-blue-grey-950: #131c23;
}

SCSS

$blue-grey: #758da3;
$blue-grey-rgb: 117, 141, 163;
$blue-grey-light: mix(#fff, $blue-grey, 20%);
$blue-grey-dark: mix(#000, $blue-grey, 20%);

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