For those who have switched to the new version but are still getting used to the layout and design, you can modify the look of the window to make it more to your liking. For example, click the three-lined Menu button in the upper-left corner of the Gmail window to show or hide the text labels next to the icons on the left side of the window.
The new Gmail offers three different styles — Default, Comfortable and Compact — that you can use to adjust the way new messages appear in your inbox list. To see which one you like best, click the Settings icon and choose Display Density. To change the background color of the Gmail window, select Themes from the menu under the gear icon.
Choosing Settings from the gear menu and clicking the General tab gives