#51497C

CSS

:root {
  --tangent-periwinkle: #51497c;
  --tangent-periwinkle-rgb: 81 73 124;
  --tangent-periwinkle-oklch: oklch(0.437 0.083 289.7);
}

.element {
  color: var(--tangent-periwinkle);
  background-color: hsl(249 26% 39%);
  border-color: oklch(0.437 0.083 289.7);
}

Tailwind CSS v4

@theme {
  --color-tangent-periwinkle: #51497c;
  --color-tangent-periwinkle-50: #f5f1ff;
  --color-tangent-periwinkle-100: #e8e4ff;
  --color-tangent-periwinkle-200: #d4cff6;
  --color-tangent-periwinkle-300: #b7b0df;
  --color-tangent-periwinkle-400: #9d96cd;
  --color-tangent-periwinkle-500: #857dba;
  --color-tangent-periwinkle-600: #716a9d;
  --color-tangent-periwinkle-700: #5a547e;
  --color-tangent-periwinkle-800: #413e5e;
  --color-tangent-periwinkle-900: #2d2a42;
  --color-tangent-periwinkle-950: #1a182a;
}

SCSS

$tangent-periwinkle: #51497c;
$tangent-periwinkle-rgb: 81, 73, 124;
$tangent-periwinkle-light: mix(#fff, $tangent-periwinkle, 20%);
$tangent-periwinkle-dark: mix(#000, $tangent-periwinkle, 20%);

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