Port mobile article styles from Cloud to Server

The mobile article styles for the help center theme in the Cloud version and the Server version are different.

To achieve a more similar page appearance, some style changes need to be made to the server article style:

• Article content inner padding (this is only needed when the sidebars are shown)

• Article content width (currently at 80% on server)

• Panel macro shouldn't have 100% width

Server:

Cloud: