#689FD7

CSS

:root {
  --blue-bay: #689fd7;
  --blue-bay-rgb: 104 159 215;
  --blue-bay-oklch: oklch(0.687 0.102 249.9);
}

.element {
  color: var(--blue-bay);
  background-color: hsl(210 58% 63%);
  border-color: oklch(0.687 0.102 249.9);
}

Tailwind CSS v4

@theme {
  --color-blue-bay: #689fd7;
  --color-blue-bay-50: #e1f8ff;
  --color-blue-bay-100: #d0ebff;
  --color-blue-bay-200: #b5d8ff;
  --color-blue-bay-300: #92bbea;
  --color-blue-bay-400: #6fa3d8;
  --color-blue-bay-500: #4e8ac7;
  --color-blue-bay-600: #4275a8;
  --color-blue-bay-700: #355e87;
  --color-blue-bay-800: #234564;
  --color-blue-bay-900: #173046;
  --color-blue-bay-950: #081c2e;
}

SCSS

$blue-bay: #689fd7;
$blue-bay-rgb: 104, 159, 215;
$blue-bay-light: mix(#fff, $blue-bay, 20%);
$blue-bay-dark: mix(#000, $blue-bay, 20%);

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