Fix close button on small screen

fix #55

frontend/src/TaskDisplay.svelte

@@ -51,9 +51,13 @@
     }
     .header {
         display: flex;
-        width: 100%;
         flex-direction: row;
     }
+    @media only screen and (max-width: 600px) {
+        .header {
+            margin-right: 40px;
+        }
+    }
     .header div {
         flex-grow: 1;
     }