#2A71A6

CSS

:root {
  --muted-blue: #2a71a6;
  --muted-blue-rgb: 42 113 166;
  --muted-blue-oklch: oklch(0.53 0.109 244.8);
}

.element {
  color: var(--muted-blue);
  background-color: hsl(206 60% 41%);
  border-color: oklch(0.53 0.109 244.8);
}

Tailwind CSS v4

@theme {
  --color-muted-blue: #2a71a6;
  --color-muted-blue-50: #ddf9ff;
  --color-muted-blue-100: #cbecff;
  --color-muted-blue-200: #afd9ff;
  --color-muted-blue-300: #89bdec;
  --color-muted-blue-400: #64a5da;
  --color-muted-blue-500: #3e8dc9;
  --color-muted-blue-600: #3677aa;
  --color-muted-blue-700: #2b5f88;
  --color-muted-blue-800: #1b4665;
  --color-muted-blue-900: #123147;
  --color-muted-blue-950: #041d2e;
}

SCSS

$muted-blue: #2a71a6;
$muted-blue-rgb: 42, 113, 166;
$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);
}