#999AA6

CSS

:root {
  --dark-ages: #999aa6;
  --dark-ages-rgb: 153 154 166;
  --dark-ages-oklch: oklch(0.689 0.017 282.1);
}

.element {
  color: var(--dark-ages);
  background-color: hsl(235 7% 63%);
  border-color: oklch(0.689 0.017 282.1);
}

Tailwind CSS v4

@theme {
  --color-dark-ages: #999aa6;
  --color-dark-ages-50: #f4f4fa;
  --color-dark-ages-100: #e7e7ee;
  --color-dark-ages-200: #d3d3dc;
  --color-dark-ages-300: #b6b6c0;
  --color-dark-ages-400: #9c9da9;
  --color-dark-ages-500: #848592;
  --color-dark-ages-600: #70717b;
  --color-dark-ages-700: #595a63;
  --color-dark-ages-800: #414248;
  --color-dark-ages-900: #2d2d32;
  --color-dark-ages-950: #1a1a1e;
}

SCSS

$dark-ages: #999aa6;
$dark-ages-rgb: 153, 154, 166;
$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);
}