#9AB5EA

CSS

:root {
  --pastel-blue: #9ab5ea;
  --pastel-blue-rgb: 154 181 234;
  --pastel-blue-oklch: oklch(0.772 0.082 263.6);
}

.element {
  color: var(--pastel-blue);
  background-color: hsl(220 66% 76%);
  border-color: oklch(0.772 0.082 263.6);
}

Tailwind CSS v4

@theme {
  --color-pastel-blue: #9ab5ea;
  --color-pastel-blue-50: #eaf5ff;
  --color-pastel-blue-100: #dbe8ff;
  --color-pastel-blue-200: #c4d4f8;
  --color-pastel-blue-300: #a3b7e2;
  --color-pastel-blue-400: #859ed0;
  --color-pastel-blue-500: #6a86bd;
  --color-pastel-blue-600: #5a719f;
  --color-pastel-blue-700: #485a80;
  --color-pastel-blue-800: #32425f;
  --color-pastel-blue-900: #222e43;
  --color-pastel-blue-950: #111b2b;
}

SCSS

$pastel-blue: #9ab5ea;
$pastel-blue-rgb: 154, 181, 234;
$pastel-blue-light: mix(#fff, $pastel-blue, 20%);
$pastel-blue-dark: mix(#000, $pastel-blue, 20%);

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