#2A71A4

CSS

:root {
  --muted-blue: #2a71a4;
  --muted-blue-rgb: 42 113 164;
  --muted-blue-oklch: oklch(0.529 0.106 243.8);
}

.element {
  color: var(--muted-blue);
  background-color: hsl(205 59% 40%);
  border-color: oklch(0.529 0.106 243.8);
}

Tailwind CSS v4

@theme {
  --color-muted-blue: #2a71a4;
  --color-muted-blue-50: #ddf9ff;
  --color-muted-blue-100: #ccecff;
  --color-muted-blue-200: #afdaff;
  --color-muted-blue-300: #8abdeb;
  --color-muted-blue-400: #64a5d9;
  --color-muted-blue-500: #3e8dc7;
  --color-muted-blue-600: #3677a8;
  --color-muted-blue-700: #2b5f87;
  --color-muted-blue-800: #1b4664;
  --color-muted-blue-900: #123146;
  --color-muted-blue-950: #041d2e;
}

SCSS

$muted-blue: #2a71a4;
$muted-blue-rgb: 42, 113, 164;
$muted-blue-light: mix(#fff, $muted-blue, 20%);
$muted-blue-dark: mix(#000, $muted-blue, 20%);

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