Hi Shaik,

You can use CSS and SASS for this. Easiest is to just add it in the 'Style’ section of your element:

But best is to create a class and add this to your element. Classes are reusable and keep your app more maintainable. You would need Koala or Gulp as an additional piece of software for compiling sass files, or Mendix’ Calypso: see the link for more information on this https://docs.mendix.com/howto/front-end/calypso#1-introduction