#3B6FA4

CSS

:root {
  --naval: #3b6fa4;
  --naval-rgb: 59 111 164;
  --naval-oklch: oklch(0.53 0.101 250.7);
}

.element {
  color: var(--naval);
  background-color: hsl(210 47% 44%);
  border-color: oklch(0.53 0.101 250.7);
}

Tailwind CSS v4

@theme {
  --color-naval: #3b6fa4;
  --color-naval-50: #e1f8ff;
  --color-naval-100: #d1ebff;
  --color-naval-200: #b6d8ff;
  --color-naval-300: #93bbea;
  --color-naval-400: #70a3d8;
  --color-naval-500: #4f8ac7;
  --color-naval-600: #4475a8;
  --color-naval-700: #365e87;
  --color-naval-800: #244564;
  --color-naval-900: #183046;
  --color-naval-950: #091c2d;
}

SCSS

$naval: #3b6fa4;
$naval-rgb: 59, 111, 164;
$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);
}