What style to set the buttons?

Question

css

I made a button in the form of an image
But there is a problem appeared white indents What style to prescribe for the button so that the white indents disappear?

Answer 1

In general, you can set a transparent background in the picture itself.
Here is the instruction:
sitestroyblog.ru/how-to-make-transparent-background

Answer 2

padding: 0;
border: none;
background-color: transparent;