Google is performing lot of layout and design changes nowadays. You can observe the changes in the new Google Search theme; the new navigation on Google Search, Calender, Google+ and Gmail. Now, they are going to introduce a new, modern look of Gmail, same as available for Google Calender. The new look for Gmail is available in preview mode.
Google, significantly, works on the feedback from the users and most of it’s changes come after the user response. The change in Gmail appearance is the mix of the opinions of users and Google, as the Search giant has also matched the look with Google+, just what it did with its Search and Calender services. It means, a new clutter-free, minimalistic design which is common in all Google products.
According to Jason Cornwell, the User Experience Designer at Google, "That’s one of the reasons we’re embarking on a series of interface updates to help strip out unnecessary clutter and make Gmail as beautiful as it is powerful. This is part of a Google-wide effort to bring you an experience that’s more focused, elastic, and effortless across all of our products. The changes are not going to happen all at once." [Source]
You can preview the new look by going to Mail Setting » Themes and choose among the items labeling “Preview” and “Preview (dense)”.
What do you think of this new design? Also know how to revert back the older look of Gmail.