#4578A9

CSS

:root {
  --into-the-blue: #4578a9;
  --into-the-blue-rgb: 69 120 169;
  --into-the-blue-oklch: oklch(0.559 0.094 249);
}

.element {
  color: var(--into-the-blue);
  background-color: hsl(209 42% 47%);
  border-color: oklch(0.559 0.094 249);
}

Tailwind CSS v4

@theme {
  --color-into-the-blue: #4578a9;
  --color-into-the-blue-50: #e2f8ff;
  --color-into-the-blue-100: #d1ebff;
  --color-into-the-blue-200: #b7d8fc;
  --color-into-the-blue-300: #94bbe7;
  --color-into-the-blue-400: #72a3d4;
  --color-into-the-blue-500: #518bc2;
  --color-into-the-blue-600: #4575a4;
  --color-into-the-blue-700: #375e83;
  --color-into-the-blue-800: #254561;
  --color-into-the-blue-900: #193044;
  --color-into-the-blue-950: #091c2c;
}

SCSS

$into-the-blue: #4578a9;
$into-the-blue-rgb: 69, 120, 169;
$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);
}