Improve responsive gallery layout

index.html

@@ -5,7 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1" />
     <meta name="theme-color" content="#07100f" />
     <title>Fractalier — Mathematical Fractal Generator</title>
-    <link rel="stylesheet" href="style.css?v=39" />
+    <link rel="stylesheet" href="style.css?v=40" />
   </head>
   <body>
     <main>
@@ -134,6 +134,6 @@
         <span id="storage-status">checking local storage…</span>
       </footer>
     </main>
-    <script src="app.js?v=39"></script>
+    <script src="app.js?v=40"></script>
   </body>
 </html>