Improve alt text form accessibility with long texts (#27095)

app/javascript/styles/mastodon/components.scss

@@ -5965,6 +5965,7 @@ a.status-card {
 .report-modal__comment {
   box-sizing: border-box;
   width: 50%;
+  min-width: 50%;
 
   @media screen and (width <= 480px) {
     width: 100%;
@@ -6033,6 +6034,14 @@ a.status-card {
     min-height: 100px;
     max-height: 50vh;
     border: 0;
+
+    @media screen and (height <= 600px) {
+      max-height: 20vh;
+    }
+
+    @media screen and (max-width: $no-columns-breakpoint) {
+      max-height: 20vh;
+    }
   }
 
   .setting-toggle {