#3C709E

CSS

:root {
  --muted-blue: #3c709e;
  --muted-blue-rgb: 60 112 158;
  --muted-blue-oklch: oklch(0.53 0.092 247.2);
}

.element {
  color: var(--muted-blue);
  background-color: hsl(208 45% 43%);
  border-color: oklch(0.53 0.092 247.2);
}

Tailwind CSS v4

@theme {
  --color-muted-blue: #3c709e;
  --color-muted-blue-50: #e2f8ff;
  --color-muted-blue-100: #d1ebff;
  --color-muted-blue-200: #b7d8fb;
  --color-muted-blue-300: #93bce5;
  --color-muted-blue-400: #71a4d2;
  --color-muted-blue-500: #518bc0;
  --color-muted-blue-600: #4576a2;
  --color-muted-blue-700: #375e82;
  --color-muted-blue-800: #254560;
  --color-muted-blue-900: #193043;
  --color-muted-blue-950: #091c2b;
}

SCSS

$muted-blue: #3c709e;
$muted-blue-rgb: 60, 112, 158;
$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);
}