1  $zindex-navbar: 1000;
 2  $zindex-dropdown: 1000;
 3  $zindex-navbar-fixed: 1030;
 4  $zindex-modal-background: 1040;
 5  $zindex-modal: 1050;
 6  $zindex-alerts: 1060;
 7  $zindex-popover: 1060;
 8  $zindex-tooltip: 1070;
 9  
10  $zindex-top: 10000;