#005290

CSS

:root {
  --dark-denim: #005290;
  --dark-denim-rgb: 0 82 144;
  --dark-denim-oklch: oklch(0.432 0.122 250);
}

.element {
  color: var(--dark-denim);
  background-color: hsl(206 100% 28%);
  border-color: oklch(0.432 0.122 250);
}

Tailwind CSS v4

@theme {
  --color-dark-denim: #005290;
  --color-dark-denim-50: #ddf8ff;
  --color-dark-denim-100: #cbebff;
  --color-dark-denim-200: #afd8ff;
  --color-dark-denim-300: #89bcf5;
  --color-dark-denim-400: #63a3e4;
  --color-dark-denim-500: #3d8ad3;
  --color-dark-denim-600: #3575b2;
  --color-dark-denim-700: #2a5e8f;
  --color-dark-denim-800: #1a456a;
  --color-dark-denim-900: #11304b;
  --color-dark-denim-950: #041c31;
}

SCSS

$dark-denim: #005290;
$dark-denim-rgb: 0, 82, 144;
$dark-denim-light: mix(#fff, $dark-denim, 20%);
$dark-denim-dark: mix(#000, $dark-denim, 20%);

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