#4E79AA

CSS

:root {
  --into-the-blue: #4e79aa;
  --into-the-blue-rgb: 78 121 170;
  --into-the-blue-oklch: oklch(0.566 0.09 252.6);
}

.element {
  color: var(--into-the-blue);
  background-color: hsl(212 37% 49%);
  border-color: oklch(0.566 0.09 252.6);
}

Tailwind CSS v4

@theme {
  --color-into-the-blue: #4e79aa;
  --color-into-the-blue-50: #e4f7ff;
  --color-into-the-blue-100: #d4eaff;
  --color-into-the-blue-200: #bbd7fb;
  --color-into-the-blue-300: #98bae5;
  --color-into-the-blue-400: #78a2d3;
  --color-into-the-blue-500: #5989c0;
  --color-into-the-blue-600: #4c74a2;
  --color-into-the-blue-700: #3c5d82;
  --color-into-the-blue-800: #294461;
  --color-into-the-blue-900: #1c2f44;
  --color-into-the-blue-950: #0c1c2c;
}

SCSS

$into-the-blue: #4e79aa;
$into-the-blue-rgb: 78, 121, 170;
$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);
}