improve layout

src/skins/vector/css/matrix-react-sdk/views/rooms/RoomPreviewBar.css

@@ -16,10 +16,25 @@ limitations under the License.
 
 .mx_RoomPreviewBar {
     text-align: center;
+    height: 176px;
+
+    -webkit-align-items: center;
+    align-items: center;
+
+    flex-direction: column;
+    -webkit-flex-direction: column;
+    
+    justify-content: center;
+    -webkit-justify-content: center;
+
+    display: -webkit-box;
+    display: -moz-box;
+    display: -ms-flexbox;
+    display: -webkit-flex;
+    display: flex;
 }
 
-.mx_RoomPreviewBar_preview_text {
-    color: #a4a4a4;
+.mx_RoomPreviewBar_wrapper {
 }
 
 .mx_RoomPreviewBar_invite_text {
@@ -30,6 +45,11 @@ limitations under the License.
     color: #ff0064;
 }
 
+.mx_RoomPreviewBar_preview_text {
+    margin-top: 25px;
+    color: #a4a4a4;
+}
+
 .mx_RoomPreviewBar_join_text a {
     text-decoration: underline;
     cursor: pointer;