diff --git a/blocks/login/block_login.php b/blocks/login/block_login.php
index 47f8588cc9d..56831f9b727 100644
--- a/blocks/login/block_login.php
+++ b/blocks/login/block_login.php
@@ -78,20 +78,24 @@ class block_login extends block_base {
 
             $this->content->text .= "\n".'<form class="loginform" id="login" method="post" action="'.get_login_url().'" '.$autocomplete.'>';
 
-            $this->content->text .= '<div class="c1 fld username"><label for="login_username">'.$strusername.'</label>';
-            $this->content->text .= '<input type="text" name="username" id="login_username" value="'.s($username).'" /></div>';
+            $this->content->text .= '<div class="form-group"><label for="login_username">'.$strusername.'</label>';
+            $this->content->text .= '<input type="text" name="username" id="login_username" class="form-control" value="'.s($username).'" /></div>';
 
-            $this->content->text .= '<div class="c1 fld password"><label for="login_password">'.get_string('password').'</label>';
+            $this->content->text .= '<div class="form-group"><label for="login_password">'.get_string('password').'</label>';
 
-            $this->content->text .= '<input type="password" name="password" id="login_password" value="" '.$autocomplete.' /></div>';
+            $this->content->text .= '<input type="password" name="password" id="login_password" class="form-control" value="" '.$autocomplete.' /></div>';
 
             if (isset($CFG->rememberusername) and $CFG->rememberusername == 2) {
                 $checked = $username ? 'checked="checked"' : '';
-                $this->content->text .= '<div class="c1 rememberusername"><input type="checkbox" name="rememberusername" id="rememberusername" value="1" '.$checked.'/>';
-                $this->content->text .= ' <label for="rememberusername">'.get_string('rememberusername', 'admin').'</label></div>';
+                $this->content->text .= '<div class="form-check-inline">';
+                $this->content->text .= '<input type="checkbox" name="rememberusername" id="rememberusername" class="form-check-input" value="1" '.$checked.'/>';
+                $this->content->text .= ' <label for="rememberusername" class="form-check-label">'.get_string('rememberusername', 'admin').'</label>';
+                $this->content->text .= '</div>';
             }
 
-            $this->content->text .= '<div class="c1 btn"><input type="submit" value="'.get_string('login').'" /></div>';
+            $this->content->text .= '<div class="form-group">';
+            $this->content->text .= '<input type="submit" class="btn btn-primary" value="'.get_string('login').'" />';
+            $this->content->text .= '</div>';
 
             $this->content->text .= "</form>\n";
 
diff --git a/theme/boost/scss/moodle/undo.scss b/theme/boost/scss/moodle/undo.scss
index 9556e7be3dc..982e6bff12b 100644
--- a/theme/boost/scss/moodle/undo.scss
+++ b/theme/boost/scss/moodle/undo.scss
@@ -100,37 +100,6 @@ fieldset.hidden {
     visibility: inherit;
 }
 
-
-/* .controls vs .controls
- *
- * in expanding course list, can be fixed in renderer though
- */
-
-
-/* .btn vs .btn
- *
- * links, inputs and buttons are commonly styled with .btn in
- * bootstrap but it seems that some buttons in Moodle are
- * wrapped in div.btn e.g. the login block's "login" button
- */
-
-div.c1.btn {
-    display: block;
-    padding: 0;
-    margin-bottom: 0;
-    font-size: inherit;
-    line-height: inherit;
-    text-align: inherit;
-    cursor: default;
-    color: inherit;
-    text-shadow: inherit;
-    background-color: inherit;
-    background-image: none;
-    background-repeat: no-repeat;
-    border: none;
-    border-radius: 0;
-    box-shadow: none;
-}
 /* .container vs .container
  *
  * bootstrap uses .container to set the width of the layout at 960px or so, Moodle uses it
diff --git a/theme/bootstrapbase/less/moodle/undo.less b/theme/bootstrapbase/less/moodle/undo.less
index b9e28136e4b..35fd45da4f1 100644
--- a/theme/bootstrapbase/less/moodle/undo.less
+++ b/theme/bootstrapbase/less/moodle/undo.less
@@ -100,37 +100,6 @@ fieldset.hidden {
     visibility: inherit;
 }
 
-
-/* .controls vs .controls
- *
- * in expanding course list, can be fixed in renderer though
- */
-
-
-/* .btn vs .btn
- *
- * links, inputs and buttons are commonly styled with .btn in
- * bootstrap but it seems that some buttons in Moodle are
- * wrapped in div.btn e.g. the login block's "login" button
- */
-
-div.c1.btn {
-    display: block;
-    padding: 0;
-    margin-bottom: 0;
-    font-size: inherit;
-    line-height: inherit;
-    text-align: inherit;
-    cursor: default;
-    color: inherit;
-    text-shadow: inherit;
-    background-color: inherit;
-    background-image: none;
-    background-repeat: no-repeat;
-    border: none;
-    border-radius: 0;
-    box-shadow: none;
-}
 /* .container vs .container
  *
  * bootstrap uses .container to set the width of the layout at 960px or so, Moodle uses it
diff --git a/theme/bootstrapbase/style/moodle.css b/theme/bootstrapbase/style/moodle.css
index aea53973af8..4a9da99226d 100644
--- a/theme/bootstrapbase/style/moodle.css
+++ b/theme/bootstrapbase/style/moodle.css
@@ -13506,33 +13506,6 @@ fieldset.hidden {
   display: inherit;
   visibility: inherit;
 }
-/* .controls vs .controls
- *
- * in expanding course list, can be fixed in renderer though
- */
-/* .btn vs .btn
- *
- * links, inputs and buttons are commonly styled with .btn in
- * bootstrap but it seems that some buttons in Moodle are
- * wrapped in div.btn e.g. the login block's "login" button
- */
-div.c1.btn {
-  display: block;
-  padding: 0;
-  margin-bottom: 0;
-  font-size: inherit;
-  line-height: inherit;
-  text-align: inherit;
-  cursor: default;
-  color: inherit;
-  text-shadow: inherit;
-  background-color: inherit;
-  background-image: none;
-  background-repeat: no-repeat;
-  border: none;
-  border-radius: 0;
-  box-shadow: none;
-}
 /* .container vs .container
  *
  * bootstrap uses .container to set the width of the layout at 960px or so, Moodle uses it