Update app.css

app.css

@@ -38,11 +38,8 @@ h1 {
     background-color: white;
     border-radius: 4px;
     margin: 10px 0;
-    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
-}
-
-.card-content {
     padding: 15px;
+    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
 }
 
 .card-content h3 {
@@ -65,6 +62,16 @@ h1 {
     text-decoration: underline;
 }
 
+.dead-link {
+    border: 2px solid #D32F2F;
+}
+
+.dead-link .card-content h3,
+.dead-link .card-content p,
+.dead-link .card-content a {
+    color: #D32F2F;
+}
+
 @media screen and (max-width: 600px) {
     .card-content h3 {
         font-size: 1em;