#1B0099

CSS

:root {
  --dramatic-blue: #1b0099;
  --dramatic-blue-rgb: 27 0 153;
  --dramatic-blue-oklch: oklch(0.319 0.207 270.9);
}

.element {
  color: var(--dramatic-blue);
  background-color: hsl(251 100% 30%);
  border-color: oklch(0.319 0.207 270.9);
}

Tailwind CSS v4

@theme {
  --color-dramatic-blue: #1b0099;
  --color-dramatic-blue-50: #e1f2ff;
  --color-dramatic-blue-100: #d1e4ff;
  --color-dramatic-blue-200: #b7ceff;
  --color-dramatic-blue-300: #95aeff;
  --color-dramatic-blue-400: #7391ff;
  --color-dramatic-blue-500: #5872ff;
  --color-dramatic-blue-600: #4a61e2;
  --color-dramatic-blue-700: #3b4eb6;
  --color-dramatic-blue-800: #263989;
  --color-dramatic-blue-900: #192761;
  --color-dramatic-blue-950: #0b1443;
}

SCSS

$dramatic-blue: #1b0099;
$dramatic-blue-rgb: 27, 0, 153;
$dramatic-blue-light: mix(#fff, $dramatic-blue, 20%);
$dramatic-blue-dark: mix(#000, $dramatic-blue, 20%);

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