The paper-header-panel or the paper-drawer-panel won't take the whole top edges of the browser window
问题 Hello I am studying Google's Polymer I followed their guide about Responsive Material Design Layouts But I just noticed that the paper-drawer-panel won't take the whole edge of the top part of the browser window. It has a bit of a gap. Here's my code <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1"> <title>Layout</title> <script src="bower_components