#497E8A

CSS

:root {
  --mysterious-blue: #497e8a;
  --mysterious-blue-rgb: 73 126 138;
  --mysterious-blue-oklch: oklch(0.561 0.059 213.9);
}

.element {
  color: var(--mysterious-blue);
  background-color: hsl(191 31% 41%);
  border-color: oklch(0.561 0.059 213.9);
}

Tailwind CSS v4

@theme {
  --color-mysterious-blue: #497e8a;
  --color-mysterious-blue-50: #e3faff;
  --color-mysterious-blue-100: #d3edf5;
  --color-mysterious-blue-200: #b9dbe5;
  --color-mysterious-blue-300: #95c0cb;
  --color-mysterious-blue-400: #75a8b4;
  --color-mysterious-blue-500: #55919e;
  --color-mysterious-blue-600: #497a86;
  --color-mysterious-blue-700: #3a626b;
  --color-mysterious-blue-800: #29484e;
  --color-mysterious-blue-900: #1b3236;
  --color-mysterious-blue-950: #0b1e21;
}

SCSS

$mysterious-blue: #497e8a;
$mysterious-blue-rgb: 73, 126, 138;
$mysterious-blue-light: mix(#fff, $mysterious-blue, 20%);
$mysterious-blue-dark: mix(#000, $mysterious-blue, 20%);

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