#357DAA

CSS

:root {
  --mediterranean-blue: #357daa;
  --mediterranean-blue-rgb: 53 125 170;
  --mediterranean-blue-oklch: oklch(0.564 0.1 239.5);
}

.element {
  color: var(--mediterranean-blue);
  background-color: hsl(203 52% 44%);
  border-color: oklch(0.564 0.1 239.5);
}

Tailwind CSS v4

@theme {
  --color-mediterranean-blue: #357daa;
  --color-mediterranean-blue-50: #ddfaff;
  --color-mediterranean-blue-100: #cbedff;
  --color-mediterranean-blue-200: #afdafc;
  --color-mediterranean-blue-300: #89bee6;
  --color-mediterranean-blue-400: #64a6d3;
  --color-mediterranean-blue-500: #3d8ec1;
  --color-mediterranean-blue-600: #3578a3;
  --color-mediterranean-blue-700: #2a6083;
  --color-mediterranean-blue-800: #1b4761;
  --color-mediterranean-blue-900: #123144;
  --color-mediterranean-blue-950: #041d2c;
}

SCSS

$mediterranean-blue: #357daa;
$mediterranean-blue-rgb: 53, 125, 170;
$mediterranean-blue-light: mix(#fff, $mediterranean-blue, 20%);
$mediterranean-blue-dark: mix(#000, $mediterranean-blue, 20%);

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