#40709B

CSS

:root {
  --naval: #40709b;
  --naval-rgb: 64 112 155;
  --naval-oklch: oklch(0.53 0.086 247.2);
}

.element {
  color: var(--naval);
  background-color: hsl(208 42% 43%);
  border-color: oklch(0.53 0.086 247.2);
}

Tailwind CSS v4

@theme {
  --color-naval: #40709b;
  --color-naval-50: #e3f8ff;
  --color-naval-100: #d3ebff;
  --color-naval-200: #b9d8f8;
  --color-naval-300: #96bce2;
  --color-naval-400: #75a3cf;
  --color-naval-500: #558bbc;
  --color-naval-600: #48769f;
  --color-naval-700: #3a5e80;
  --color-naval-800: #27455e;
  --color-naval-900: #1a3042;
  --color-naval-950: #0b1c2a;
}

SCSS

$naval: #40709b;
$naval-rgb: 64, 112, 155;
$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);
}