The most recent http://www.gmail.com redesign left the left sidebar very wide and with a lot of white space. The width of the content table scales only down to 720px. After that the rightmost colums, as as well as the vertical scroll bar, fall outside the page. Remarkable is the lack of a horizontal scroll bar, making these columns and the vertical scroll bar unreachable.

• The left sidebar collapses partially and expands again when the mouse moves over it. The unread mail count of the main labels stays visible, even when collapsed.
• The star column is removed.
• The content table width scales always when the size of the page changes. This way there is no need for a horizontal scroll bar and neither columns nor vertical scroll bar fall outside the page.
• The background color changes of any row where the mouse moves over.

The example screenshot shows the Google Chrome browser on Windows 8.1, taking up half the screen of a Surface Pro 3. To get the same result you might have to set 'Display mode' to 'Compact'. No indicators. No widgets. No categories. No chat. No theme. Almost all labels are either hidden or set to show only if there are unread mails. The right sidebar is collapsed by clicking on the edge button.

Similar adaptations are available for http://freestyler.ws/style/131016/wolfram-alpha-elastic-design-improvements.

• 2016-02-05: The date column accommodates wider date formats. Markup for the labels on the sidebar is re-applied to reflect a change on Google's side.
• 2015-11-25: Custom labels on the sidebar, always visible or visible due to the presence of unread mail; conform to the same markup as the main labels. Labels, when too wide for the sidebar; are clipped to the left instead of abbreviated, to prevent losing the unread mail count. All markup for the mail table, formerly defined too broad, is limited to the mail table.

Let me know if you experience any problems. In that case a screenshot might be useful.