Thread:Rappy 4187/@comment-5774380-20150715114535/@comment-957747-20150717073432

Unfortunately, no. That space ebbs and flows with different resolutions and should look the same for all users on all wikias.

Sitenotices and/or site-wide messages, such as the spoiler warning here, will need to be within the article's area. However, you are free to expand on the alotted area (with more padding or margins). Typically, that's sufficient as the notice is about the article's content.

There are some other spoiler methods, such as w:c:dev:SpoilerAlert, but they usually rely on a category structure or template on each individual page.