#3FA3E1

CSS

:root {
  --high-blue: #3fa3e1;
  --high-blue-rgb: 63 163 225;
  --high-blue-oklch: oklch(0.684 0.129 240);
}

.element {
  color: var(--high-blue);
  background-color: hsl(203 73% 56%);
  border-color: oklch(0.684 0.129 240);
}

Tailwind CSS v4

@theme {
  --color-high-blue: #3fa3e1;
  --color-high-blue-50: #d6fbff;
  --color-high-blue-100: #c3eeff;
  --color-high-blue-200: #a3dcff;
  --color-high-blue-300: #79c0f4;
  --color-high-blue-400: #4ca8e3;
  --color-high-blue-500: #008fd2;
  --color-high-blue-600: #0c79b1;
  --color-high-blue-700: #0c618f;
  --color-high-blue-800: #004869;
  --color-high-blue-900: #02324a;
  --color-high-blue-950: #001d31;
}

SCSS

$high-blue: #3fa3e1;
$high-blue-rgb: 63, 163, 225;
$high-blue-light: mix(#fff, $high-blue, 20%);
$high-blue-dark: mix(#000, $high-blue, 20%);

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