#487E8A

CSS

:root {
  --mysterious-blue: #487e8a;
  --mysterious-blue-rgb: 72 126 138;
  --mysterious-blue-oklch: oklch(0.56 0.06 213.6);
}

.element {
  color: var(--mysterious-blue);
  background-color: hsl(191 31% 41%);
  border-color: oklch(0.56 0.06 213.6);
}

Tailwind CSS v4

@theme {
  --color-mysterious-blue: #487e8a;
  --color-mysterious-blue-50: #e3faff;
  --color-mysterious-blue-100: #d2edf5;
  --color-mysterious-blue-200: #b8dbe5;
  --color-mysterious-blue-300: #95c0cb;
  --color-mysterious-blue-400: #75a8b4;
  --color-mysterious-blue-500: #54919e;
  --color-mysterious-blue-600: #487b86;
  --color-mysterious-blue-700: #39626b;
  --color-mysterious-blue-800: #28484e;
  --color-mysterious-blue-900: #1b3237;
  --color-mysterious-blue-950: #0b1e21;
}

SCSS

$mysterious-blue: #487e8a;
$mysterious-blue-rgb: 72, 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);
}