Click the User Menu, showing your name or email, at the top right corner.
Select 'Profile' from the User Menu.
The page consists of two parts.
In the profile section, you can update your details, such as email or phone number.
When you finish, click 'UPDATE PROFILE'.
In the settings section, you can choose the density of the interface.
There are three options:
Just click on the current option and then select your preferred density from the list. No need to do anything else.