Slightly improve styling on mobile devices

style.css

@@ -1,10 +1,5 @@
 @import "node_modules/ol/ol.css";
 
-html, body {
-  margin: 0;
-  height: 100%;
-}
-
 #map {
   position: absolute;
   top: 0;
@@ -41,3 +36,28 @@ aside ul li {
 h1 {
   text-align: center;
 }
+
+aside .close {
+  display: none;
+}
+
+@media (max-width: 400px) {
+  .nav-open #map {
+    left: 100%;
+  }
+
+  aside {
+    margin-left: calc(-100% + 2em);
+    width: calc(100% - 2em);
+  }
+
+  aside .close {
+    display: initial;
+  }
+
+  .nav-open aside .close {
+    position: absolute;
+    top: 0.5em;
+    right: 0.5em;
+  }
+}