Changing your theme
To change your theme you need to click on the drop down arrow next to your email address on the right hand-side of your login page.
Once you have clicked on the down arrow, you will want to click on the account settings option.
On the account settings page you will see the Google Mail Icon- with the option to click on settings next to the icon. Click on the word "settings"
On the settings page, you will see tabs accross the top of the page. Find the themes tab and click on the word themes.
The theme pictures indicate what themes are available. Click on the icon theme you would like, by clicking on the icon you will change the look of the mail page.