#1F71E4

CSS

:root {
  --deep-sky-blue: #1f71e4;
  --deep-sky-blue-rgb: 31 113 228;
  --deep-sky-blue-oklch: oklch(0.567 0.191 258.4);
}

.element {
  color: var(--deep-sky-blue);
  background-color: hsl(215 78% 51%);
  border-color: oklch(0.567 0.191 258.4);
}

Tailwind CSS v4

@theme {
  --color-deep-sky-blue: #1f71e4;
  --color-deep-sky-blue-50: #d6f7ff;
  --color-deep-sky-blue-100: #c3e9ff;
  --color-deep-sky-blue-200: #a5d5ff;
  --color-deep-sky-blue-300: #7db7ff;
  --color-deep-sky-blue-400: #519cff;
  --color-deep-sky-blue-500: #2380ff;
  --color-deep-sky-blue-600: #206dd9;
  --color-deep-sky-blue-700: #1a57ae;
  --color-deep-sky-blue-800: #084082;
  --color-deep-sky-blue-900: #052c5c;
  --color-deep-sky-blue-950: #00193f;
}

SCSS

$deep-sky-blue: #1f71e4;
$deep-sky-blue-rgb: 31, 113, 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);
}