#979AA5

CSS

:root {
  --dark-ages: #979aa5;
  --dark-ages-rgb: 151 154 165;
  --dark-ages-oklch: oklch(0.687 0.016 273.7);
}

.element {
  color: var(--dark-ages);
  background-color: hsl(227 7% 62%);
  border-color: oklch(0.687 0.016 273.7);
}

Tailwind CSS v4

@theme {
  --color-dark-ages: #979aa5;
  --color-dark-ages-50: #f4f5fa;
  --color-dark-ages-100: #e6e7ed;
  --color-dark-ages-200: #d2d4db;
  --color-dark-ages-300: #b5b7c0;
  --color-dark-ages-400: #9b9ea8;
  --color-dark-ages-500: #828691;
  --color-dark-ages-600: #6e717b;
  --color-dark-ages-700: #585a62;
  --color-dark-ages-800: #404248;
  --color-dark-ages-900: #2c2e32;
  --color-dark-ages-950: #191a1e;
}

SCSS

$dark-ages: #979aa5;
$dark-ages-rgb: 151, 154, 165;
$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);
}