style: match sidebar font-size with guidemaker-ember-template (ember-learn#879)

Author: Lukas Nys

app/styles/app.css

@@ -44,16 +44,23 @@ main a.edit-icon {
 .table-of-contents {
   list-style-type: none;
   padding-left: 0;
-  font-size: var(--font-size-lg);
+  font-size: var(--font-size-base);
   font-weight: var(--font-weight-3);
 }
 
 .sub-table-of-contents {
   padding-left: var(--spacing-1);
-  font-size: var(--font-size-md);
+  font-size: var(--font-size-base);
   font-weight: var(--font-weight-2);
 }
 
+@media (max-width: 844px) {
+  .table-of-contents,
+  .sub-table-of-contents {
+    font-size: var(--font-size-lg);
+  }
+}
+
 .sub-table-of-contents .sub-table-of-contents {
   padding-left: var(--spacing-3);
   margin-bottom: 0;