#00276E

CSS

:root {
  --dark-sapphire: #00276e;
  --dark-sapphire-rgb: 0 39 110;
  --dark-sapphire-oklch: oklch(0.302 0.13 261);
}

.element {
  color: var(--dark-sapphire);
  background-color: hsl(219 100% 22%);
  border-color: oklch(0.302 0.13 261);
}

Tailwind CSS v4

@theme {
  --color-dark-sapphire: #00276e;
  --color-dark-sapphire-50: #e2f6ff;
  --color-dark-sapphire-100: #d1e9ff;
  --color-dark-sapphire-200: #b7d5ff;
  --color-dark-sapphire-300: #94b7fb;
  --color-dark-sapphire-400: #729eeb;
  --color-dark-sapphire-500: #5284db;
  --color-dark-sapphire-600: #4670b9;
  --color-dark-sapphire-700: #385a95;
  --color-dark-sapphire-800: #25426f;
  --color-dark-sapphire-900: #192e4e;
  --color-dark-sapphire-950: #091a34;
}

SCSS

$dark-sapphire: #00276e;
$dark-sapphire-rgb: 0, 39, 110;
$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);
}