#457E8D

CSS

:root {
  --mysterious-blue: #457e8d;
  --mysterious-blue-rgb: 69 126 141;
  --mysterious-blue-oklch: oklch(0.56 0.064 216.8);
}

.element {
  color: var(--mysterious-blue);
  background-color: hsl(193 34% 41%);
  border-color: oklch(0.56 0.064 216.8);
}

Tailwind CSS v4

@theme {
  --color-mysterious-blue: #457e8d;
  --color-mysterious-blue-50: #e2faff;
  --color-mysterious-blue-100: #d1eef7;
  --color-mysterious-blue-200: #b7dbe7;
  --color-mysterious-blue-300: #93c0ce;
  --color-mysterious-blue-400: #72a8b7;
  --color-mysterious-blue-500: #5191a2;
  --color-mysterious-blue-600: #457b89;
  --color-mysterious-blue-700: #37626e;
  --color-mysterious-blue-800: #264850;
  --color-mysterious-blue-900: #1a3238;
  --color-mysterious-blue-950: #0a1e22;
}

SCSS

$mysterious-blue: #457e8d;
$mysterious-blue-rgb: 69, 126, 141;
$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);
}