#3A6FA8

CSS

:root {
  --naval: #3a6fa8;
  --naval-rgb: 58 111 168;
  --naval-oklch: oklch(0.532 0.107 252);
}

.element {
  color: var(--naval);
  background-color: hsl(211 49% 44%);
  border-color: oklch(0.532 0.107 252);
}

Tailwind CSS v4

@theme {
  --color-naval: #3a6fa8;
  --color-naval-50: #e1f8ff;
  --color-naval-100: #d0ebff;
  --color-naval-200: #b5d7ff;
  --color-naval-300: #92bbed;
  --color-naval-400: #6fa2dc;
  --color-naval-500: #4e89ca;
  --color-naval-600: #4274ab;
  --color-naval-700: #355d89;
  --color-naval-800: #234566;
  --color-naval-900: #172f47;
  --color-naval-950: #081c2f;
}

SCSS

$naval: #3a6fa8;
$naval-rgb: 58, 111, 168;
$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);
}