diff -u b/claro.info.yml b/claro.info.yml
--- b/claro.info.yml
+++ b/claro.info.yml
@@ -77,15 +77,15 @@
       component:
         css/components/dropbutton.css: false
 
-  classy/messages:
+  classy/progress:
     css:
       component:
-        css/components/messages.css: false
+        css/components/dropbutton.css: false
 
-  classy/progress:
+  classy/messages:
     css:
       component:
-        css/components/dropbutton.css: false
+        css/components/messages.css: false
 
   classy/progress:
     css:
diff -u b/css/src/components/messages.css b/css/src/components/messages.css
--- b/css/src/components/messages.css
+++ b/css/src/components/messages.css
@@ -113,0 +114,9 @@
+
+@media screen and (-ms-high-contrast: active) {
+  .messages {
+    border-width: 1px 1px 1px var(--messages-border-width);
+  }
+  .messages__header {
+    filter: grayscale(1) brightness(1.5) contrast(10);
+  }
+}
only in patch2:
unchanged:
--- /dev/null
+++ b/js/messages.js
@@ -0,0 +1,25 @@
+/**
+* DO NOT EDIT THIS FILE.
+* See the following change record for more information,
+* https://www.drupal.org/node/2815083
+* @preserve
+**/
+
+Drupal.theme.message = function (_ref, _ref2) {
+  var text = _ref.text;
+  var type = _ref2.type,
+      id = _ref2.id;
+
+  var messagesTypes = Drupal.Message.getMessageTypeLabels();
+  var messageWrapper = document.createElement('div');
+
+  messageWrapper.setAttribute('class', 'messages messages--' + type);
+  messageWrapper.setAttribute('role', type === 'error' || type === 'warning' ? 'alert' : 'status');
+  messageWrapper.setAttribute('aria-labelledby', id + '-title');
+  messageWrapper.setAttribute('data-drupal-message-id', id);
+  messageWrapper.setAttribute('data-drupal-message-type', type);
+
+  messageWrapper.innerHTML = '\n    <div class="messages__header">\n      <h2 id="' + id + '-title" class="messages__title">\n        ' + messagesTypes[type] + '\n      </h2>\n    </div>\n    <div class="messages__content">\n      ' + text + '\n    </div>\n  ';
+
+  return messageWrapper;
+};
\ No newline at end of file