#3B7CA8

CSS

:root {
  --zenith: #3b7ca8;
  --zenith-rgb: 59 124 168;
  --zenith-oklch: oklch(0.563 0.095 240.9);
}

.element {
  color: var(--zenith);
  background-color: hsl(204 48% 45%);
  border-color: oklch(0.563 0.095 240.9);
}

Tailwind CSS v4

@theme {
  --color-zenith: #3b7ca8;
  --color-zenith-50: #dff9ff;
  --color-zenith-100: #cdecff;
  --color-zenith-200: #b2dafa;
  --color-zenith-300: #8dbee5;
  --color-zenith-400: #69a6d2;
  --color-zenith-500: #448ebf;
  --color-zenith-600: #3b78a1;
  --color-zenith-700: #2f6082;
  --color-zenith-800: #1f4760;
  --color-zenith-900: #143143;
  --color-zenith-950: #061d2b;
}

SCSS

$zenith: #3b7ca8;
$zenith-rgb: 59, 124, 168;
$zenith-light: mix(#fff, $zenith, 20%);
$zenith-dark: mix(#000, $zenith, 20%);

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