changes to css and js

css/emergency-alert.css

 a, a:hover {
     border-style: none !important;
 }
+button {
+    border: none;
+    background: transparent;
+}
 .emergency-alert {
-    font-family: "Whitney SSm A";
+    font-family: "Whitney SSm A", sans-serif;
     font-size: 1rem;
     line-height: 1rem;
     margin-bottom: 0;
@@ -91,6 +95,9 @@ a, a:hover {
         justify-content: flex-end;
         padding-top: 1rem;
     }
+    .emergency-alert--high .emergency-alert__close svg {
+        color: white;
+    }
     .emergency-alert__close svg {
         background-color: rgba(0,0,0,.1);
         padding: .3rem;

css/marketing-alert.css

+button {
+    border: none;
+    background: transparent;
+}
 .marketing-alert {
-    font-family: "Whitney SSm A";
+    font-family: "Whitney SSm A", sans-serif;
     line-height: 2rem;
     padding: 1rem;
     width: 100%;
@@ -127,6 +131,7 @@
         justify-content: flex-end;
     }
     .marketing-alert__close svg {
+        color: white;
         background-color: rgba(0,0,0,.1);
         padding: .5rem;
         width: 2.4rem;

js/alert-close.js

 (function ($) {
+
     Drupal.behaviors.tuftsEmergencyAlert = {
         attach: function(context, settings) {
-           $(context).find('.emergency-alert__close svg')
+           $(context).find('.emergency-alert__close #alertCloseButton')
            .once('closeAlert')
            .click(function() {
-                $( '.emergency-alert' ).slideUp('slow');
+                $(this.closest('.emergency-alert')).slideUp('slow');
            });
       }
     };
     Drupal.behaviors.tuftsMarketingAlert = {
         attach: function(context, settings) {
-           $(context).find('.marketing-alert__close svg')
+           $(context).find('.marketing-alert__close #alertCloseButton')
            .once('closeAlert')
            .click(function() {
-                $( '.marketing-alert' ).slideUp('slow');
+                $(this.closest('.marketing-alert')).slideUp('slow');
            });
       }
     };

templates/node--emergency-alert.html.twig

@@ -23,6 +23,8 @@
     </div>
   </div>
   <div class="emergency-alert__close">
+    <button id="alertCloseButton" tabindex="1">
       {{source('@tufts_alerts/svg/alert_close.svg')}}
+    </button>
   </div>
 </article>

templates/node--marketing-alert.html.twig

@@ -17,6 +17,8 @@
     </div>
   </div>
   <div class="marketing-alert__close">
+    <button id="alertCloseButton" tabindex="2">
       {{source('@tufts_alerts/svg/alert_close.svg')}}
+    </button>
   </div>
 </article>