add mobile style

static/style/mobile.css

@@ -0,0 +1,29 @@
+/* all mobile devices */
+@media all and (min-width:0px) and (max-width: 1020px) {
+    .cover {
+        background-image: url('/img/if25_banner_no_text.png')!important;
+    }
+    .bg-transparent {
+        background-color: rgba(0, 0, 0, 0.4)!important;
+    }
+    div.flex-l.items-center {
+        text-shadow: 1px 1px 40px #000000;
+        
+    }
+}
+
+/* if edgecases occur */
+/* tablets */
+@media all and (min-width:569px) and (max-width: 768px) {
+    
+}
+
+/* phablet */
+@media all and (min-width:481px) and (max-width: 568px) {
+    
+}
+
+/* mobile phone */
+@media all and (min-width:321px) and (max-width: 480px) {
+
+}