#427BAC

CSS

:root {
  --into-the-blue: #427bac;
  --into-the-blue-rgb: 66 123 172;
  --into-the-blue-oklch: oklch(0.566 0.097 246.5);
}

.element {
  color: var(--into-the-blue);
  background-color: hsl(208 45% 47%);
  border-color: oklch(0.566 0.097 246.5);
}

Tailwind CSS v4

@theme {
  --color-into-the-blue: #427bac;
  --color-into-the-blue-50: #e0f8ff;
  --color-into-the-blue-100: #cfebff;
  --color-into-the-blue-200: #b4d9fd;
  --color-into-the-blue-300: #90bce7;
  --color-into-the-blue-400: #6da4d5;
  --color-into-the-blue-500: #4b8cc3;
  --color-into-the-blue-600: #4176a4;
  --color-into-the-blue-700: #335f84;
  --color-into-the-blue-800: #224662;
  --color-into-the-blue-900: #173044;
  --color-into-the-blue-950: #081c2c;
}

SCSS

$into-the-blue: #427bac;
$into-the-blue-rgb: 66, 123, 172;
$into-the-blue-light: mix(#fff, $into-the-blue, 20%);
$into-the-blue-dark: mix(#000, $into-the-blue, 20%);

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