throw error on empty save

view/static/style.css

@@ -224,6 +224,18 @@ code.with-line-numbers {
     background: var(--secondary);
 }
 
+.error-banner {
+    background-color: rgba(248, 81, 73, 0.1);
+    border: 1px solid rgba(248, 81, 73, 0.4);
+    color: #f85149;
+    padding: 0.75rem 1rem;
+    border-radius: 6px;
+    margin-bottom: 1rem;
+    font-size: 0.85rem;
+    display: flex;
+    align-items: center;
+}
+
 .sr-only {
     position: absolute;
     width: 1px;

view/templates/bin.html

@@ -60,10 +60,15 @@
     </script>
     {{ else }}
     <div class="content-wrapper">
+        {{ if .Error }}
+        <div class="error-banner">
+            {{ .Error }}
+        </div>
+        {{ end }}
         <form id="paste-form" action="/" method="post">
             <label for="content-editor" class="sr-only">Paste Content</label>
             <textarea id="content-editor" name="content" placeholder="Paste something interesting here..." autofocus
-                autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false"></textarea>
+                autocomplete="off" autocorrect="off" autocapitalize="off" spellcheck="false">{{ .Content }}</textarea>
         </form>
     </div>
     <script>