Update static/styles.css

static/styles.css

@@ -64,6 +64,14 @@ button:hover {
     background-color: #45a049;
 }
 
+#stop-btn {
+    background-color: #F44336;
+}
+
+#stop-btn:hover {
+    background-color: #d32f2f;
+}
+
 #reset-btn {
     background-color: #2196F3;
 }