#3D6FA1

CSS

:root {
  --naval: #3d6fa1;
  --naval-rgb: 61 111 161;
  --naval-oklch: oklch(0.53 0.096 250.1);
}

.element {
  color: var(--naval);
  background-color: hsl(210 45% 44%);
  border-color: oklch(0.53 0.096 250.1);
}

Tailwind CSS v4

@theme {
  --color-naval: #3d6fa1;
  --color-naval-50: #e2f8ff;
  --color-naval-100: #d1ebff;
  --color-naval-200: #b7d8fd;
  --color-naval-300: #94bbe8;
  --color-naval-400: #72a3d5;
  --color-naval-500: #528ac3;
  --color-naval-600: #4675a5;
  --color-naval-700: #385e84;
  --color-naval-800: #264562;
  --color-naval-900: #193045;
  --color-naval-950: #0a1c2d;
}

SCSS

$naval: #3d6fa1;
$naval-rgb: 61, 111, 161;
$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);
}