#517C80

CSS

:root {
  --submerged: #517c80;
  --submerged-rgb: 81 124 128;
  --submerged-oklch: oklch(0.556 0.048 203.3);
}

.element {
  color: var(--submerged);
  background-color: hsl(185 22% 41%);
  border-color: oklch(0.556 0.048 203.3);
}

Tailwind CSS v4

@theme {
  --color-submerged: #517c80;
  --color-submerged-50: #e6f9fc;
  --color-submerged-100: #d6edef;
  --color-submerged-200: #bedbde;
  --color-submerged-300: #9cbfc3;
  --color-submerged-400: #7da7ab;
  --color-submerged-500: #5f9094;
  --color-submerged-600: #517a7d;
  --color-submerged-700: #416164;
  --color-submerged-800: #2e4749;
  --color-submerged-900: #1f3233;
  --color-submerged-950: #0f1d1e;
}

SCSS

$submerged: #517c80;
$submerged-rgb: 81, 124, 128;
$submerged-light: mix(#fff, $submerged, 20%);
$submerged-dark: mix(#000, $submerged, 20%);

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