#E3F1F3

CSS

:root {
  --winter-s-breath: #e3f1f3;
  --winter-s-breath-rgb: 227 241 243;
  --winter-s-breath-oklch: oklch(0.948 0.015 207.1);
}

.element {
  color: var(--winter-s-breath);
  background-color: hsl(187 40% 92%);
  border-color: oklch(0.948 0.015 207.1);
}

Tailwind CSS v4

@theme {
  --color-winter-s-breath: #e3f1f3;
  --color-winter-s-breath-50: #f0f6f7;
  --color-winter-s-breath-100: #e2e9ea;
  --color-winter-s-breath-200: #cdd6d8;
  --color-winter-s-breath-300: #afbabb;
  --color-winter-s-breath-400: #95a1a3;
  --color-winter-s-breath-500: #7b898b;
  --color-winter-s-breath-600: #687476;
  --color-winter-s-breath-700: #535d5e;
  --color-winter-s-breath-800: #3d4445;
  --color-winter-s-breath-900: #2a2f30;
  --color-winter-s-breath-950: #171b1c;
}

SCSS

$winter-s-breath: #e3f1f3;
$winter-s-breath-rgb: 227, 241, 243;
$winter-s-breath-light: mix(#fff, $winter-s-breath, 20%);
$winter-s-breath-dark: mix(#000, $winter-s-breath, 20%);

.element {
  color: $winter-s-breath;
  box-shadow: 0 0 0 2px rgba($winter-s-breath, 0.35);
}