#5F789D

CSS

:root {
  --montreux-blue: #5f789d;
  --montreux-blue-rgb: 95 120 157;
  --montreux-blue-oklch: oklch(0.568 0.065 258);
}

.element {
  color: var(--montreux-blue);
  background-color: hsl(216 25% 49%);
  border-color: oklch(0.568 0.065 258);
}

Tailwind CSS v4

@theme {
  --color-montreux-blue: #5f789d;
  --color-montreux-blue-50: #ebf6ff;
  --color-montreux-blue-100: #dce9fe;
  --color-montreux-blue-200: #c4d5f1;
  --color-montreux-blue-300: #a4b9d9;
  --color-montreux-blue-400: #87a0c5;
  --color-montreux-blue-500: #6b88b1;
  --color-montreux-blue-600: #5b7396;
  --color-montreux-blue-700: #495c78;
  --color-montreux-blue-800: #344359;
  --color-montreux-blue-900: #232f3e;
  --color-montreux-blue-950: #121b27;
}

SCSS

$montreux-blue: #5f789d;
$montreux-blue-rgb: 95, 120, 157;
$montreux-blue-light: mix(#fff, $montreux-blue, 20%);
$montreux-blue-dark: mix(#000, $montreux-blue, 20%);

.element {
  color: $montreux-blue;
  box-shadow: 0 0 0 2px rgba($montreux-blue, 0.35);
}