Adjust CSS for accordion elements

Ghost User
2019-08-28T19:58:43+02:00

Adds a missing bottom border.

#### Previous behaviour
![Screenshot_2019-08-16_at_12.32.27](/uploads/6c400ac64c9f4f25791c885ff5ffe831/Screenshot_2019-08-16_at_12.32.27.png)

#### New behaviour
![Screenshot_2019-08-16_at_12.32.16](/...