Some content pushes article container wide

[stephaniehobson]

Description

The <pre> on http://www.mozilla.org/en-US/security/ is pushing the .mzp-c-article container wide on tablet.

Steps to reproduce

1. In the regular article layout template put a <pre> tag with really wide content in it.
2. Re-size the screen so that the article should shrink to less than $content-md.

Expected result

Content contained inside the article.

Actual result

The article has a max-width of $content-md so it will not obey the width of the screen, instead stretching to $content-md wide.

[stephaniehobson]

Here's the fix from bedrock:

.mzp-c-article {
    width: $content-md;
    max-width: 100%;
}