diff --git a/lib/outputrenderers.php b/lib/outputrenderers.php
index 9ac6a6502f6..5f6c98fbff3 100644
--- a/lib/outputrenderers.php
+++ b/lib/outputrenderers.php
@@ -656,8 +656,8 @@ class core_renderer extends renderer_base {
         if (isset($CFG->maintenance_later) and $CFG->maintenance_later > time()) {
             $timeleft = $CFG->maintenance_later - time();
             // If timeleft less than 30 sec, set the class on block to error to highlight.
-            $errorclass = ($timeleft < 30) ? 'error' : 'warning';
-            $output .= $this->box_start($errorclass . ' moodle-has-zindex maintenancewarning');
+            $errorclass = ($timeleft < 30) ? 'alert-error alert-danger' : 'alert-warning';
+            $output .= $this->box_start($errorclass . ' moodle-has-zindex maintenancewarning m-a-1 alert');
             $a = new stdClass();
             $a->hour = (int)($timeleft / 3600);
             $a->min = (int)(($timeleft / 60) % 60);
diff --git a/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-debug.js b/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-debug.js
index 430f15982af..434bb7066f4 100644
--- a/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-debug.js
+++ b/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-debug.js
@@ -49,11 +49,13 @@ Y.extend(MAINTENANCEMODETIMER, Y.Base, {
         }
         // Set error class to highlight the importance.
         if (this.timeleftinsec < 30) {
-            this.maintenancenode.addClass('error')
-                    .removeClass('warning');
+            this.maintenancenode.addClass('alert-error')
+                    .addClass('alert-danger')
+                    .removeClass('alert-warning');
         } else {
-            this.maintenancenode.addClass('warning')
-                    .removeClass('error');
+            this.maintenancenode.addClass('alert-warning')
+                    .removeClass('alert-error')
+                    .removeClass('alert-danger');
         }
     }
 });
diff --git a/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-min.js b/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-min.js
index 9435047b816..1a107a0092f 100644
--- a/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-min.js
+++ b/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer-min.js
@@ -1 +1 @@
-YUI.add("moodle-core-maintenancemodetimer",function(e,t){var n=function(){n.superclass.constructor.apply(this,arguments)};e.extend(n,e.Base,{timeleftinsec:0,maintenancenode:e.one(".box.maintenancewarning"),initializer:function(t){this.maintenancenode&&(this.timeleftinsec=t.timeleftinsec,this.maintenancenode.setAttribute("aria-live","polite"),e.later(1e3,this,"updatetimer",null,!0))},updatetimer:function(){this.timeleftinsec-=1;if(this.timeleftinsec<=0)this.maintenancenode.set("text",M.util.get_string("sitemaintenance","admin"));else{var e={};e.sec=this.timeleftinsec%60,e.min=Math.floor(this.timeleftinsec/60)%60,e.hour=Math.floor(this.timeleftinsec/3600),e.hour>0?this.maintenancenode.set("text",M.util.get_string("maintenancemodeisscheduledlong","admin",e)):this.maintenancenode.set("text",M.util.get_string("maintenancemodeisscheduled","admin",e))}this.timeleftinsec<30?this.maintenancenode.addClass("error").removeClass("warning"):this.maintenancenode.addClass("warning").removeClass("error")}}),M.core=M.core||{},M.core.maintenancemodetimer=M.core.maintenancemodetimer||function(e){return new n(e)}},"@VERSION@",{requires:["base","node"]});
+YUI.add("moodle-core-maintenancemodetimer",function(e,t){var n=function(){n.superclass.constructor.apply(this,arguments)};e.extend(n,e.Base,{timeleftinsec:0,maintenancenode:e.one(".box.maintenancewarning"),initializer:function(t){this.maintenancenode&&(this.timeleftinsec=t.timeleftinsec,this.maintenancenode.setAttribute("aria-live","polite"),e.later(1e3,this,"updatetimer",null,!0))},updatetimer:function(){this.timeleftinsec-=1;if(this.timeleftinsec<=0)this.maintenancenode.set("text",M.util.get_string("sitemaintenance","admin"));else{var e={};e.sec=this.timeleftinsec%60,e.min=Math.floor(this.timeleftinsec/60)%60,e.hour=Math.floor(this.timeleftinsec/3600),e.hour>0?this.maintenancenode.set("text",M.util.get_string("maintenancemodeisscheduledlong","admin",e)):this.maintenancenode.set("text",M.util.get_string("maintenancemodeisscheduled","admin",e))}this.timeleftinsec<30?this.maintenancenode.addClass("alert-error").addClass("alert-danger").removeClass("alert-warning"):this.maintenancenode.addClass("alert-warning").removeClass("alert-error").removeClass("alert-danger")}}),M.core=M.core||{},M.core.maintenancemodetimer=M.core.maintenancemodetimer||function(e){return new n(e)}},"@VERSION@",{requires:["base","node"]});
diff --git a/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer.js b/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer.js
index 430f15982af..434bb7066f4 100644
--- a/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer.js
+++ b/lib/yui/build/moodle-core-maintenancemodetimer/moodle-core-maintenancemodetimer.js
@@ -49,11 +49,13 @@ Y.extend(MAINTENANCEMODETIMER, Y.Base, {
         }
         // Set error class to highlight the importance.
         if (this.timeleftinsec < 30) {
-            this.maintenancenode.addClass('error')
-                    .removeClass('warning');
+            this.maintenancenode.addClass('alert-error')
+                    .addClass('alert-danger')
+                    .removeClass('alert-warning');
         } else {
-            this.maintenancenode.addClass('warning')
-                    .removeClass('error');
+            this.maintenancenode.addClass('alert-warning')
+                    .removeClass('alert-error')
+                    .removeClass('alert-danger');
         }
     }
 });
diff --git a/lib/yui/src/maintenancemodetimer/js/maintenancemodetimer.js b/lib/yui/src/maintenancemodetimer/js/maintenancemodetimer.js
index 9d4899de1b7..a35d518583a 100644
--- a/lib/yui/src/maintenancemodetimer/js/maintenancemodetimer.js
+++ b/lib/yui/src/maintenancemodetimer/js/maintenancemodetimer.js
@@ -47,11 +47,13 @@ Y.extend(MAINTENANCEMODETIMER, Y.Base, {
         }
         // Set error class to highlight the importance.
         if (this.timeleftinsec < 30) {
-            this.maintenancenode.addClass('error')
-                    .removeClass('warning');
+            this.maintenancenode.addClass('alert-error')
+                    .addClass('alert-danger')
+                    .removeClass('alert-warning');
         } else {
-            this.maintenancenode.addClass('warning')
-                    .removeClass('error');
+            this.maintenancenode.addClass('alert-warning')
+                    .removeClass('alert-error')
+                    .removeClass('alert-danger');
         }
     }
 });
diff --git a/theme/boost/scss/moodle/admin.scss b/theme/boost/scss/moodle/admin.scss
index 977acd52df5..ae43bf4dc6f 100644
--- a/theme/boost/scss/moodle/admin.scss
+++ b/theme/boost/scss/moodle/admin.scss
@@ -785,8 +785,6 @@
 }
 
 .maintenancewarning {
-    padding: 3px 1em;
-    text-align: center;
     position: fixed;
     bottom: 0;
     right: 0;