#646C82

CSS

:root {
  --ashen-whisper: #646c82;
  --ashen-whisper-rgb: 100 108 130;
  --ashen-whisper-oklch: oklch(0.533 0.036 269.4);
}

.element {
  color: var(--ashen-whisper);
  background-color: hsl(224 13% 45%);
  border-color: oklch(0.533 0.036 269.4);
}

Tailwind CSS v4

@theme {
  --color-ashen-whisper: #646c82;
  --color-ashen-whisper-50: #f1f5ff;
  --color-ashen-whisper-100: #e3e7f4;
  --color-ashen-whisper-200: #ced4e4;
  --color-ashen-whisper-300: #b0b7ca;
  --color-ashen-whisper-400: #969eb4;
  --color-ashen-whisper-500: #7c869f;
  --color-ashen-whisper-600: #697186;
  --color-ashen-whisper-700: #545a6b;
  --color-ashen-whisper-800: #3d424f;
  --color-ashen-whisper-900: #2a2e37;
  --color-ashen-whisper-950: #171a22;
}

SCSS

$ashen-whisper: #646c82;
$ashen-whisper-rgb: 100, 108, 130;
$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);
}