<link rel="stylesheet" type="text/css" href="assets/fonts/materialdesignicons/materialdesignicons.min.css">
we have used material icons as default icon family in atlas. you can change the icons used in atlas by changing values in variables
//Icons
$icon-font: 'Material Design Icons';
//Icon Mappings
$icon-chevron-down: "\F140";
$icon-chevron-up: "\F143";
$icon-chevron-left: "\F141";
$icon-chevron-right: "\F142";
$icon-sidebar-pin: "\F930";
$icon-sidebar-pin-off: "\F92F";
$icon-search: "\F349";
$icon-arrow-right: "\F054";
$icon-arrow-left: "\F04D";
$icon-close: "\F156";
$icon-close-circle: "\F15a";
$icon-check: "\F12c";
$icon-check-circle: "\F5e0";
$icon-circle: "\F130";
$icon-fullscreen: "\F293";
$icon-fullscreen-close: "\F294";
$icon-reload: "\F453";
$icon-menu: "\F35C";