What is Transparent in CSS?
In CSS, transparency is used on an element by using the CSS opacity property, which ranges from (0.0 to 1.0), where the opacity: 0.0 makes the element 100% transparent, and opacity: 1.0 makes the element untransparent.
Make Button Transparent
As you know, you can make a button transparent very easily by using opacity, for more understanding you can see the example below:
<button text="Button" style="background:red; opacity:0.8;" type="button" />