#6DA1C2

CSS

:root {
  --wandering-river: #6da1c2;
  --wandering-river-rgb: 109 161 194;
  --wandering-river-oklch: oklch(0.685 0.074 237.2);
}

.element {
  color: var(--wandering-river);
  background-color: hsl(203 41% 59%);
  border-color: oklch(0.685 0.074 237.2);
}

Tailwind CSS v4

@theme {
  --color-wandering-river: #6da1c2;
  --color-wandering-river-50: #e3f9ff;
  --color-wandering-river-100: #d2ecfe;
  --color-wandering-river-200: #b8d9f1;
  --color-wandering-river-300: #95bdda;
  --color-wandering-river-400: #74a5c5;
  --color-wandering-river-500: #548eb1;
  --color-wandering-river-600: #487896;
  --color-wandering-river-700: #396078;
  --color-wandering-river-800: #274758;
  --color-wandering-river-900: #1a313e;
  --color-wandering-river-950: #0b1d27;
}

SCSS

$wandering-river: #6da1c2;
$wandering-river-rgb: 109, 161, 194;
$wandering-river-light: mix(#fff, $wandering-river, 20%);
$wandering-river-dark: mix(#000, $wandering-river, 20%);

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