#126BCB

CSS

:root {
  --matt-blue: #126bcb;
  --matt-blue-rgb: 18 107 203;
  --matt-blue-oklch: oklch(0.534 0.168 255.3);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(211 84% 43%);
  border-color: oklch(0.534 0.168 255.3);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #126bcb;
  --color-matt-blue-50: #d7f8ff;
  --color-matt-blue-100: #c5ebff;
  --color-matt-blue-200: #a6d7ff;
  --color-matt-blue-300: #7fb9ff;
  --color-matt-blue-400: #54a0ff;
  --color-matt-blue-500: #2585f2;
  --color-matt-blue-600: #2271cc;
  --color-matt-blue-700: #1b5aa4;
  --color-matt-blue-800: #0b437a;
  --color-matt-blue-900: #072e56;
  --color-matt-blue-950: #001a3a;
}

SCSS

$matt-blue: #126bcb;
$matt-blue-rgb: 18, 107, 203;
$matt-blue-light: mix(#fff, $matt-blue, 20%);
$matt-blue-dark: mix(#000, $matt-blue, 20%);

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