I am trying to display two buttons in a row with an image on them. I use:
.outer {
  background-color: gray;
  padding: 10px;
}
.inner {
  background-color: blue;
  padding: 10px;
}
.tab {
  background-color: red;
}<div class="outer">
  <div class="tab">
    <button>
       <img src="http://www.insideredbox.com/images/ball_red.png">
      </button>
    <button>
       <img src="http://www.insideredbox.com/images/ball_red.png">
      </button>
  </div>
  <div class="inner">
    Test123
  </div>
</div>Code works fine but why is there a space of 1px at the bottom line of red border? Moreover, how can I also erase the red space between the two buttons?

 
     
     
     
    