#42719C

CSS

:root {
  --naval: #42719c;
  --naval-rgb: 66 113 156;
  --naval-oklch: oklch(0.534 0.085 247.7);
}

.element {
  color: var(--naval);
  background-color: hsl(209 41% 44%);
  border-color: oklch(0.534 0.085 247.7);
}

Tailwind CSS v4

@theme {
  --color-naval: #42719c;
  --color-naval-50: #e3f8ff;
  --color-naval-100: #d3ebff;
  --color-naval-200: #b9d8f8;
  --color-naval-300: #96bbe2;
  --color-naval-400: #75a3cf;
  --color-naval-500: #568bbc;
  --color-naval-600: #49769f;
  --color-naval-700: #3a5e7f;
  --color-naval-800: #28455e;
  --color-naval-900: #1b3042;
  --color-naval-950: #0b1c2a;
}

SCSS

$naval: #42719c;
$naval-rgb: 66, 113, 156;
$naval-light: mix(#fff, $naval, 20%);
$naval-dark: mix(#000, $naval, 20%);

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