#2873E4

CSS

:root {
  --deep-sky-blue: #2873e4;
  --deep-sky-blue-rgb: 40 115 228;
  --deep-sky-blue-oklch: oklch(0.574 0.187 259);
}

.element {
  color: var(--deep-sky-blue);
  background-color: hsl(216 78% 53%);
  border-color: oklch(0.574 0.187 259);
}

Tailwind CSS v4

@theme {
  --color-deep-sky-blue: #2873e4;
  --color-deep-sky-blue-50: #d7f7ff;
  --color-deep-sky-blue-100: #c5e9ff;
  --color-deep-sky-blue-200: #a7d5ff;
  --color-deep-sky-blue-300: #80b6ff;
  --color-deep-sky-blue-400: #559cff;
  --color-deep-sky-blue-500: #2b80ff;
  --color-deep-sky-blue-600: #266dd7;
  --color-deep-sky-blue-700: #1e57ad;
  --color-deep-sky-blue-800: #0d4081;
  --color-deep-sky-blue-900: #082c5b;
  --color-deep-sky-blue-950: #00193e;
}

SCSS

$deep-sky-blue: #2873e4;
$deep-sky-blue-rgb: 40, 115, 228;
$deep-sky-blue-light: mix(#fff, $deep-sky-blue, 20%);
$deep-sky-blue-dark: mix(#000, $deep-sky-blue, 20%);

.element {
  color: $deep-sky-blue;
  box-shadow: 0 0 0 2px rgba($deep-sky-blue, 0.35);
}