How to reset all default styles of the HTML5 button element

Question

Scenario

I use the element which appeares just as plain text with an \"+\" on right end.
On click a div element expands and reveals so

Answer 1

button::-moz-focus-inner,
input::-moz-focus-inner {
  border: 0;
  padding: 0;
}

add this one also in css it will solve your problem.