#6759D3

CSS

:root {
  --warm-blue: #6759d3;
  --warm-blue-rgb: 103 89 211;
  --warm-blue-oklch: oklch(0.544 0.181 283.8);
}

.element {
  color: var(--warm-blue);
  background-color: hsl(247 58% 59%);
  border-color: oklch(0.544 0.181 283.8);
}

Tailwind CSS v4

@theme {
  --color-warm-blue: #6759d3;
  --color-warm-blue-50: #f0efff;
  --color-warm-blue-100: #e2e0ff;
  --color-warm-blue-200: #cdc9ff;
  --color-warm-blue-300: #b0a8ff;
  --color-warm-blue-400: #938cff;
  --color-warm-blue-500: #7c6df7;
  --color-warm-blue-600: #695dd0;
  --color-warm-blue-700: #544aa8;
  --color-warm-blue-800: #3a367e;
  --color-warm-blue-900: #282559;
  --color-warm-blue-950: #16133c;
}

SCSS

$warm-blue: #6759d3;
$warm-blue-rgb: 103, 89, 211;
$warm-blue-light: mix(#fff, $warm-blue, 20%);
$warm-blue-dark: mix(#000, $warm-blue, 20%);

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