#1870F3

CSS

:root {
  --deep-sky-blue: #1870f3;
  --deep-sky-blue-rgb: 24 112 243;
  --deep-sky-blue-oklch: oklch(0.576 0.212 259.5);
}

.element {
  color: var(--deep-sky-blue);
  background-color: hsl(216 90% 52%);
  border-color: oklch(0.576 0.212 259.5);
}

Tailwind CSS v4

@theme {
  --color-deep-sky-blue: #1870f3;
  --color-deep-sky-blue-50: #d4f6ff;
  --color-deep-sky-blue-100: #c1e9ff;
  --color-deep-sky-blue-200: #a1d4ff;
  --color-deep-sky-blue-300: #79b5ff;
  --color-deep-sky-blue-400: #4a9aff;
  --color-deep-sky-blue-500: #167cff;
  --color-deep-sky-blue-600: #1769e4;
  --color-deep-sky-blue-700: #1354b8;
  --color-deep-sky-blue-800: #003e89;
  --color-deep-sky-blue-900: #022b61;
  --color-deep-sky-blue-950: #001743;
}

SCSS

$deep-sky-blue: #1870f3;
$deep-sky-blue-rgb: 24, 112, 243;
$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);
}