#444674

CSS

:root {
  --tangent-periwinkle: #444674;
  --tangent-periwinkle-rgb: 68 70 116;
  --tangent-periwinkle-oklch: oklch(0.414 0.076 280.6);
}

.element {
  color: var(--tangent-periwinkle);
  background-color: hsl(237 26% 36%);
  border-color: oklch(0.414 0.076 280.6);
}

Tailwind CSS v4

@theme {
  --color-tangent-periwinkle: #444674;
  --color-tangent-periwinkle-50: #f1f3ff;
  --color-tangent-periwinkle-100: #e3e5ff;
  --color-tangent-periwinkle-200: #cfd1f5;
  --color-tangent-periwinkle-300: #b1b3de;
  --color-tangent-periwinkle-400: #969acb;
  --color-tangent-periwinkle-500: #7d80b8;
  --color-tangent-periwinkle-600: #696d9b;
  --color-tangent-periwinkle-700: #54577d;
  --color-tangent-periwinkle-800: #3c405d;
  --color-tangent-periwinkle-900: #292c41;
  --color-tangent-periwinkle-950: #17192a;
}

SCSS

$tangent-periwinkle: #444674;
$tangent-periwinkle-rgb: 68, 70, 116;
$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);
}