#00256A

CSS

:root {
  --dark-sapphire: #00256a;
  --dark-sapphire-rgb: 0 37 106;
  --dark-sapphire-oklch: oklch(0.294 0.127 261);
}

.element {
  color: var(--dark-sapphire);
  background-color: hsl(219 100% 21%);
  border-color: oklch(0.294 0.127 261);
}

Tailwind CSS v4

@theme {
  --color-dark-sapphire: #00256a;
  --color-dark-sapphire-50: #e2f6ff;
  --color-dark-sapphire-100: #d2e9ff;
  --color-dark-sapphire-200: #b8d5ff;
  --color-dark-sapphire-300: #95b7f9;
  --color-dark-sapphire-400: #739ee9;
  --color-dark-sapphire-500: #5484da;
  --color-dark-sapphire-600: #4870b8;
  --color-dark-sapphire-700: #395a94;
  --color-dark-sapphire-800: #26426e;
  --color-dark-sapphire-900: #192e4d;
  --color-dark-sapphire-950: #0a1a33;
}

SCSS

$dark-sapphire: #00256a;
$dark-sapphire-rgb: 0, 37, 106;
$dark-sapphire-light: mix(#fff, $dark-sapphire, 20%);
$dark-sapphire-dark: mix(#000, $dark-sapphire, 20%);

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