The usability of accordion elements in a mobile environment could be improved by expanding the first section by default. This is because it can provide the user with a clear indication of what kind of content is hidden in the accordion, and encourage them to explore the rest of the sections1. Expanding the first section by default can also reduce the user’s cognitive load, as they do not have to make a decision on which section to open first2. Moreover, expanding the first section by default can improve the accessibility of the accordion, as it can help screen reader users to understand the structure and purpose of the widget3.

Using the Back browser button to collapse content is not a good option, as it can confuse the user and break the expected browser behavior. The Back button is meant to navigate to the previous page, not to collapse an accordion section4. Using the Back button to collapse content can also create navigation issues, as the user might lose their current page or state4.

Moving an expanded section to the top of the screen is also not a good option, as it can disrupt the user’s spatial memory and orientation. Moving an expanded section to the top of the screen can change the order and position of the accordion sections, which can make it harder for the user to find and access the section they want5. It can also create a jarring and inconsistent user experience, as the user might not expect the content to move around the screen5.