fixÑ add misssiong env variables and fix index breakpoint

Author: dcoa

.env

@@ -49,3 +49,5 @@ TWITTER_URL=''
 USER_INFO_COOKIE_NAME=''
 OPTIMIZELY_FULL_STACK_SDK_KEY=''
 SHOW_UNGRADED_ASSIGNMENT_PROGRESS=''
+# Fallback in local style files
+PARAGON_THEME_URLS={}

.env.development

@@ -51,3 +51,5 @@ CHAT_RESPONSE_URL='http://localhost:18000/api/learning_assistant/v1/course_id'
 PRIVACY_POLICY_URL='http://localhost:18000/privacy'
 OPTIMIZELY_FULL_STACK_SDK_KEY=''
 SHOW_UNGRADED_ASSIGNMENT_PROGRESS=''
+# Fallback in local style files
+PARAGON_THEME_URLS={}

src/index.scss

@@ -439,7 +439,7 @@
   height: 56px !important;
 }
 
-@include media-breakpoint-down(xs) {
+@media (--pgn-size-breakpoint-max-width-xs) {
   .course-outline-tab .pgn__card {
     .pgn__card-header {
       display: block;