How to change icon size inside a button?

im not able to change the icon size of a button.
I put a custom class for that and it does nothing…

<button class="carousel-footer-button button button-clear icon ion-heart"></button>


  font-size: 40px !important;

/how can i overwrite the original style? !important is not doing anything …

What is carousel-footer-button?
Have you tried to put the icon as it won tag inside the button and extend icon class as big-icon ?

<button class="carousel-footer-button button button-clear"><i class="big-icon ion-heart"> </i></button>

This is my custom class that is trying to override the original style…
I didnt try what you suggested. I will give it a try.