#699FD6

CSS

:root {
  --blue-bay: #699fd6;
  --blue-bay-rgb: 105 159 214;
  --blue-bay-oklch: oklch(0.687 0.1 249.9);
}

.element {
  color: var(--blue-bay);
  background-color: hsl(210 57% 63%);
  border-color: oklch(0.687 0.1 249.9);
}

Tailwind CSS v4

@theme {
  --color-blue-bay: #699fd6;
  --color-blue-bay-50: #e1f8ff;
  --color-blue-bay-100: #d0ebff;
  --color-blue-bay-200: #b6d8fe;
  --color-blue-bay-300: #92bbea;
  --color-blue-bay-400: #70a3d7;
  --color-blue-bay-500: #4f8ac6;
  --color-blue-bay-600: #4375a7;
  --color-blue-bay-700: #365e86;
  --color-blue-bay-800: #244563;
  --color-blue-bay-900: #183046;
  --color-blue-bay-950: #091c2d;
}

SCSS

$blue-bay: #699fd6;
$blue-bay-rgb: 105, 159, 214;
$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);
}