Make all elements in bootstrap have sharp corners

bootstrap-square.css

/*
    Bootflat 1.0.1
    Designed & Built by flathemes, http://www.flathemes.com
    Licensed under MIT License, http://opensource.org/licenses/mit-license.html

    Thanks for supporting our website and enjoy!
*/
/*------------------------------------*\
    $default
\*------------------------------------*/
.img-thumbnail,
.btn,
.btn-group .btn,
.btn-group .dropdown-menu,
.btn-group .btn,
.btn-group .btn:first-child:not(:last-child),
.btn-group .btn:last-child:not(:first-child),
.table-bordered,
.table-bordered tr:first-child th:first-child,
.table-bordered tr:first-child th:last-child,
.table-bordered tr:last-child td:first-child,
.table-bordered tr:last-child td:last-child,
.input-group .btn,
.input-group .dropdown-menu,
.input-group .form-control,
.input-group .input-group-addon,
.dropdown-menu,
.dropdown-menu .dropdown-submenu .dropdown-menu,
.form .form-control,
.form .btn,
.form-control,
.label,
.badge,
.alert,
.alert .btn,
.progress,
.breadcrumb,
.tooltip .tooltip-inner,
.popover,
.nav-list-panel,
.nav-tabs li > a,
.tabs-below .nav-tabs li > a,
.tabs-right .nav-tabs li > a,
.tabs-left .nav-tabs li > a,
.nav-tabs .dropdown-menu,
.tabs-below .nav-tabs .dropdown-menu,
.nav-pills li a,
.nav-pills .dropdown-menu,
.navbar,
.navbar .dropdown-menu,
.pagination,
.pagination li:first-child a,
.pagination li:first-child span,
.pagination li:last-child a, 
.pagination li:last-child span,
.pager li a,
.pager li a:hover,
.pager li a:focus,
.panel,
.panel-group .panel,
.panel-group .panel-heading,
.panel-group .panel-body,
/*------------------------------------*\
    $extend
\*------------------------------------*/
.breadcrumb-arrow li:first-child a {
    -webkit-border-radius: 0;
    -moz-border-radius: 0;
    border-radius: 0;
}

Thanks

Where's the code I need to put sharp edges on my transparent boxes on my Github website.