Very Blue

CSS

:root {
  --very-blue: #33365b;
  --very-blue-rgb: 51 54 91;
  --very-blue-oklch: oklch(0.348 0.064 279);
}

.element {
  color: var(--very-blue);
  background-color: hsl(236 28% 28%);
  border-color: oklch(0.348 0.064 279);
}

Tailwind CSS v4

@theme {
  --color-very-blue: #33365b;
  --color-very-blue-50: #f1f3ff;
  --color-very-blue-100: #e3e6fe;
  --color-very-blue-200: #cfd2f0;
  --color-very-blue-300: #b1b4d8;
  --color-very-blue-400: #969bc5;
  --color-very-blue-500: #7d82b1;
  --color-very-blue-600: #696e95;
  --color-very-blue-700: #545878;
  --color-very-blue-800: #3c4059;
  --color-very-blue-900: #2a2c3e;
  --color-very-blue-950: #171927;
}

SCSS

$very-blue: #33365b;
$very-blue-rgb: 51, 54, 91;
$very-blue-light: mix(#fff, $very-blue, 20%);
$very-blue-dark: mix(#000, $very-blue, 20%);

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