civicrm_backdrop.css

/**
  * Backdrop CSS which is needed on non-CiviCRM pages, too.
  */

/* Override Backdrop's CSS for CRM-provided UI. */
#crm-container .ui-state-default,
#crm-container .ui-widget-content .ui-state-default,
#crm-container .ui-widget-header .ui-state-default {
  background: #e6e6e6 url(../bower_components/jquery-ui/themes/smoothness/images/ui-bg_glass_75_e6e6e6_1x400.png) 50% 50% repeat-x;
}

/**
 * Prevent contact name overlapping the breadcrumb.
 * @see https: //lab.civicrm.org/dev/backdrop/-/issues/84
 */
#crm-container div.crm-summary-contactname-block {
  margin-top: 0px !important;
}