Having problems resizing an FA icon

Webix JS
#1

Trying to center and change the size of some FA icons, but when I do the following in CSS it centers, but increasing the size just moves the image down lower within the button itself.

CSS:

.webix_view .webix_img_btn {
	text-align: center;
	font-size: 2.0em;
}

JS:

                      { 
                        	view: "button", 
                        	type: "icon",
                        	icon: "volume-down",
			        width: 145, 
				align: "center",
                        },                    
                    	{ 
                        	view: "button", 
                        	type: "icon",
                        	icon: "volume-up",
			        width: 145, 
                        	align: "center" 
                        }
#2

Hello!
The point is that you add font-size to the button. You need to add it to the icon

.webix_view .webix_img_btn {
    text-align: center;
  }
  .webix_view .webix_img_btn .webix_icon_btn {
    font-size: 2.0em;
  }

https://snippet.webix.com/50wkfryh

#3

That makes a lot of sense, thanks so much!