#679FD4

CSS

:root {
  --blue-bay: #679fd4;
  --blue-bay-rgb: 103 159 212;
  --blue-bay-oklch: oklch(0.685 0.098 248.1);
}

.element {
  color: var(--blue-bay);
  background-color: hsl(209 56% 62%);
  border-color: oklch(0.685 0.098 248.1);
}

Tailwind CSS v4

@theme {
  --color-blue-bay: #679fd4;
  --color-blue-bay-50: #e1f8ff;
  --color-blue-bay-100: #d0ebff;
  --color-blue-bay-200: #b5d8fe;
  --color-blue-bay-300: #91bce8;
  --color-blue-bay-400: #6ea4d6;
  --color-blue-bay-500: #4d8bc4;
  --color-blue-bay-600: #4276a6;
  --color-blue-bay-700: #345e85;
  --color-blue-bay-800: #234562;
  --color-blue-bay-900: #173045;
  --color-blue-bay-950: #081c2d;
}

SCSS

$blue-bay: #679fd4;
$blue-bay-rgb: 103, 159, 212;
$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);
}