#979BA4

CSS

:root {
  --dark-ages: #979ba4;
  --dark-ages-rgb: 151 155 164;
  --dark-ages-oklch: oklch(0.689 0.014 266.7);
}

.element {
  color: var(--dark-ages);
  background-color: hsl(222 7% 62%);
  border-color: oklch(0.689 0.014 266.7);
}

Tailwind CSS v4

@theme {
  --color-dark-ages: #979ba4;
  --color-dark-ages-50: #f3f5f9;
  --color-dark-ages-100: #e6e8ed;
  --color-dark-ages-200: #d2d4da;
  --color-dark-ages-300: #b4b7bf;
  --color-dark-ages-400: #9b9ea7;
  --color-dark-ages-500: #828690;
  --color-dark-ages-600: #6e727a;
  --color-dark-ages-700: #585b61;
  --color-dark-ages-800: #404247;
  --color-dark-ages-900: #2c2e31;
  --color-dark-ages-950: #191b1d;
}

SCSS

$dark-ages: #979ba4;
$dark-ages-rgb: 151, 155, 164;
$dark-ages-light: mix(#fff, $dark-ages, 20%);
$dark-ages-dark: mix(#000, $dark-ages, 20%);

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