#636C80

CSS

:root {
  --ashen-whisper: #636c80;
  --ashen-whisper-rgb: 99 108 128;
  --ashen-whisper-oklch: oklch(0.531 0.033 266.1);
}

.element {
  color: var(--ashen-whisper);
  background-color: hsl(221 13% 45%);
  border-color: oklch(0.531 0.033 266.1);
}

Tailwind CSS v4

@theme {
  --color-ashen-whisper: #636c80;
  --color-ashen-whisper-50: #f1f5ff;
  --color-ashen-whisper-100: #e3e8f3;
  --color-ashen-whisper-200: #ced4e3;
  --color-ashen-whisper-300: #b0b7c9;
  --color-ashen-whisper-400: #959eb3;
  --color-ashen-whisper-500: #7c869d;
  --color-ashen-whisper-600: #697285;
  --color-ashen-whisper-700: #545b6a;
  --color-ashen-whisper-800: #3d424e;
  --color-ashen-whisper-900: #2a2e36;
  --color-ashen-whisper-950: #171b21;
}

SCSS

$ashen-whisper: #636c80;
$ashen-whisper-rgb: 99, 108, 128;
$ashen-whisper-light: mix(#fff, $ashen-whisper, 20%);
$ashen-whisper-dark: mix(#000, $ashen-whisper, 20%);

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