#426F9B

CSS

:root {
  --naval: #426f9b;
  --naval-rgb: 66 111 155;
  --naval-oklch: oklch(0.529 0.086 249.2);
}

.element {
  color: var(--naval);
  background-color: hsl(210 40% 43%);
  border-color: oklch(0.529 0.086 249.2);
}

Tailwind CSS v4

@theme {
  --color-naval: #426f9b;
  --color-naval-50: #e4f8ff;
  --color-naval-100: #d4ebff;
  --color-naval-200: #bad8f8;
  --color-naval-300: #97bbe3;
  --color-naval-400: #77a3cf;
  --color-naval-500: #578abd;
  --color-naval-600: #4b759f;
  --color-naval-700: #3b5e80;
  --color-naval-800: #29455f;
  --color-naval-900: #1b3042;
  --color-naval-950: #0c1c2b;
}

SCSS

$naval: #426f9b;
$naval-rgb: 66, 111, 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);
}