Merge branch 'fixsidebar-btn'

This fixes git#1916.

Signed-off-by: Johannes Schindelin <[email protected]>

Author: dscho

assets/sass/sidebar.scss

@@ -51,9 +51,9 @@ aside.sidebar.active {
     border: none;
     left: 0;
     width: 1.6rem;
-    &:focus + .sidebar {
-      @include responsive-sidebar-ui;
-    }
+  }
+  .sidebar-btn:focus + .sidebar, .sidebar:focus-within {
+    @include responsive-sidebar-ui;
   }
   aside{
     &.sidebar {