#659DE3

CSS

:root {
  --blue-bay: #659de3;
  --blue-bay-rgb: 101 157 227;
  --blue-bay-oklch: oklch(0.687 0.12 254.7);
}

.element {
  color: var(--blue-bay);
  background-color: hsl(213 69% 64%);
  border-color: oklch(0.687 0.12 254.7);
}

Tailwind CSS v4

@theme {
  --color-blue-bay: #659de3;
  --color-blue-bay-50: #e0f7ff;
  --color-blue-bay-100: #cfeaff;
  --color-blue-bay-200: #b4d7ff;
  --color-blue-bay-300: #90baf4;
  --color-blue-bay-400: #6ca1e4;
  --color-blue-bay-500: #4a88d3;
  --color-blue-bay-600: #4073b2;
  --color-blue-bay-700: #335c8f;
  --color-blue-bay-800: #21446a;
  --color-blue-bay-900: #162f4b;
  --color-blue-bay-950: #071b31;
}

SCSS

$blue-bay: #659de3;
$blue-bay-rgb: 101, 157, 227;
$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);
}