#296EB7

CSS

:root {
  --matt-blue: #296eb7;
  --matt-blue-rgb: 41 110 183;
  --matt-blue-oklch: oklch(0.532 0.134 252.8);
}

.element {
  color: var(--matt-blue);
  background-color: hsl(211 63% 44%);
  border-color: oklch(0.532 0.134 252.8);
}

Tailwind CSS v4

@theme {
  --color-matt-blue: #296eb7;
  --color-matt-blue-50: #dcf8ff;
  --color-matt-blue-100: #caebff;
  --color-matt-blue-200: #aed8ff;
  --color-matt-blue-300: #88bbfb;
  --color-matt-blue-400: #62a2eb;
  --color-matt-blue-500: #3b88db;
  --color-matt-blue-600: #3474b9;
  --color-matt-blue-700: #295c95;
  --color-matt-blue-800: #19446f;
  --color-matt-blue-900: #102f4e;
  --color-matt-blue-950: #031b34;
}

SCSS

$matt-blue: #296eb7;
$matt-blue-rgb: 41, 110, 183;
$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);
}