#4D78A1

CSS

:root {
  --into-the-blue: #4d78a1;
  --into-the-blue-rgb: 77 120 161;
  --into-the-blue-oklch: oklch(0.559 0.08 248.3);
}

.element {
  color: var(--into-the-blue);
  background-color: hsl(209 35% 47%);
  border-color: oklch(0.559 0.08 248.3);
}

Tailwind CSS v4

@theme {
  --color-into-the-blue: #4d78a1;
  --color-into-the-blue-50: #e5f8ff;
  --color-into-the-blue-100: #d5ebff;
  --color-into-the-blue-200: #bbd8f6;
  --color-into-the-blue-300: #99bbdf;
  --color-into-the-blue-400: #79a3cc;
  --color-into-the-blue-500: #5a8bb9;
  --color-into-the-blue-600: #4d759c;
  --color-into-the-blue-700: #3d5e7d;
  --color-into-the-blue-800: #2a455d;
  --color-into-the-blue-900: #1c3041;
  --color-into-the-blue-950: #0d1c29;
}

SCSS

$into-the-blue: #4d78a1;
$into-the-blue-rgb: 77, 120, 161;
$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);
}