#396FA7

CSS

:root {
  --naval: #396fa7;
  --naval-rgb: 57 111 167;
  --naval-oklch: oklch(0.531 0.106 251.2);
}

.element {
  color: var(--naval);
  background-color: hsl(211 49% 44%);
  border-color: oklch(0.531 0.106 251.2);
}

Tailwind CSS v4

@theme {
  --color-naval: #396fa7;
  --color-naval-50: #e1f8ff;
  --color-naval-100: #d0ebff;
  --color-naval-200: #b5d8ff;
  --color-naval-300: #91bbed;
  --color-naval-400: #6ea3db;
  --color-naval-500: #4d8aca;
  --color-naval-600: #4275aa;
  --color-naval-700: #345d89;
  --color-naval-800: #234565;
  --color-naval-900: #173047;
  --color-naval-950: #081c2e;
}

SCSS

$naval: #396fa7;
$naval-rgb: 57, 111, 167;
$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);
}