#3599A2

CSS

:root {
  --baltic: #3599a2;
  --baltic-rgb: 53 153 162;
  --baltic-oklch: oklch(0.63 0.091 203.7);
}

.element {
  color: var(--baltic);
  background-color: hsl(185 51% 42%);
  border-color: oklch(0.63 0.091 203.7);
}

Tailwind CSS v4

@theme {
  --color-baltic: #3599a2;
  --color-baltic-50: #d8fdff;
  --color-baltic-100: #c6f1f7;
  --color-baltic-200: #a7e0e7;
  --color-baltic-300: #7dc5ce;
  --color-baltic-400: #54aeb7;
  --color-baltic-500: #1c97a1;
  --color-baltic-600: #1d8088;
  --color-baltic-700: #17676d;
  --color-baltic-800: #0e4c50;
  --color-baltic-900: #093437;
  --color-baltic-950: #002022;
}

SCSS

$baltic: #3599a2;
$baltic-rgb: 53, 153, 162;
$baltic-light: mix(#fff, $baltic, 20%);
$baltic-dark: mix(#000, $baltic, 20%);

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