#42A2E4

CSS

:root {
  --high-blue: #42a2e4;
  --high-blue-rgb: 66 162 228;
  --high-blue-oklch: oklch(0.685 0.132 242.4);
}

.element {
  color: var(--high-blue);
  background-color: hsl(204 75% 58%);
  border-color: oklch(0.685 0.132 242.4);
}

Tailwind CSS v4

@theme {
  --color-high-blue: #42a2e4;
  --color-high-blue-50: #d6faff;
  --color-high-blue-100: #c3eeff;
  --color-high-blue-200: #a4dbff;
  --color-high-blue-300: #7bbff6;
  --color-high-blue-400: #4ea7e6;
  --color-high-blue-500: #0d8ed5;
  --color-high-blue-600: #1378b4;
  --color-high-blue-700: #106091;
  --color-high-blue-800: #03476b;
  --color-high-blue-900: #04314b;
  --color-high-blue-950: #001d32;
}

SCSS

$high-blue: #42a2e4;
$high-blue-rgb: 66, 162, 228;
$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);
}