#E9F1F3

CSS

:root {
  --morning-mist: #e9f1f3;
  --morning-mist-rgb: 233 241 243;
  --morning-mist-oklch: oklch(0.953 0.009 214.3);
}

.element {
  color: var(--morning-mist);
  background-color: hsl(192 29% 93%);
  border-color: oklch(0.953 0.009 214.3);
}

Tailwind CSS v4

@theme {
  --color-morning-mist: #e9f1f3;
  --color-morning-mist-50: #f2f6f7;
  --color-morning-mist-100: #e5e9ea;
  --color-morning-mist-200: #d0d5d7;
  --color-morning-mist-300: #b3b9ba;
  --color-morning-mist-400: #99a0a2;
  --color-morning-mist-500: #80888a;
  --color-morning-mist-600: #6c7375;
  --color-morning-mist-700: #565c5d;
  --color-morning-mist-800: #3f4344;
  --color-morning-mist-900: #2b2e2f;
  --color-morning-mist-950: #191b1c;
}

SCSS

$morning-mist: #e9f1f3;
$morning-mist-rgb: 233, 241, 243;
$morning-mist-light: mix(#fff, $morning-mist, 20%);
$morning-mist-dark: mix(#000, $morning-mist, 20%);

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