Try to add the following code snippet to the Custom CSS area for dekstop device only in Theme Settings to change the button

body .tabs-layout-tabs .tabs li {
    margin-right:0;
}

body .tabs-layout-tabs .tabs li a {
    padding-top: 17px;
 padding-bottom: 17px;
    padding-left:30px;
    padding-right:30px;
    line-height: 1;
}

body .tabs-layout-tabs .tabs li.active a {
      background-color: #c13030;
   color: white;
}

body .tabs-layout-tabs .tabs li a:after {
    content:none;
}