html - Firefox absolute position bug -

i'm having problem absolute position in firefox. works different chrome, ie or opera.

i'm talking navigation here http://mapylasky.xdiv.cz/

in browsers expect firefox in 1 line. in firefox not in place.

.menu-item{      position: absolute;      color: #000;  }   .menu-item .icon{      position: absolute;      background-image: url('<?php echo get_template_directory_uri(); ?>/img/menu/menu-icons.png');   }    .menu-item .desc{       position: absolute;       font-size: 16px;    }  .container{     width: 1100px;     margin: 0 auto;     position: relative; }   .menu-item .icon{    height: 56px;   }  .menu-item.prvni{     left: 11px;     top: 21px; }  .menu-item.prvni .icon{     width: 193px;     height: 92px;     background-position-x: 452px; }  .menu-item.prvni .desc{     left: 0px;     top: 0px; } 

html

        <div class="navigation-background">             <div class="container">                       <a href="javascript: void(0)" onclick="scrolltoanchor('uvod');">                         <div class="menu-item prvni active" id="home-menu">                             <div class="icon"></div>                         </div>                     </a>                </div>         </div> 

what doing wrong?

jsfiffle: https://jsfiddle.net/2cne0fnc/

firefox not support background-position-x, support background-position

simply change background-position-x: 100px background-position:100px 0 include both x , y position.

working example : https://jsfiddle.net/41xb9xfb/