Don't make changes to graphical layout without prior discussion. Please note that this guideline applies only to a handful of pages such as Wikipedia:Community Portal, Help:Contents, Wikipedia:Featured content (and the rest of the featured-related pages), and any other pages that have page design and layout beyond just how test and images are arranged. While articles can improve by this normal way of little, unorganized edits, page design is different.
By contrast, when many users edit a page for layout, it gets worse. This process of attrition is what this guideline is meant to prevent. It is better to have a page that looks like this than like this.
Such, we highly recommend users to not make these sort of style edits on whim. This may seem un-wiki, but the resulting hodgepodge of design elements that are not cohesively linked, formatted, colored, and organized far outweigh this. Instead, we encourage talking over changes on the the appropriate talk page, and creating a draft in a sandbox. This encourages consensus and would put a lid on the gradual attrition of the page's design by many uncollaborative edits.
What is it for?
This guideline applies to only a handful of pages. You should not make unapproved design edit to these types oof pages.
- Main Page. It is permenantly locked to guard against vandalism, and as a side effect the design is in stasis. With the exception of a major, prolonged redesign, the design has stayed constant.
- Community Portal. This page is notorious for am ever-changing look. Don't add to it!
- Help:Contents. This page needs to be user-friendly. There's a long running dispute over icons, and the needed simplicity is often eroded.
- Featured content, Featured articles, Featured lists, and to a lesser extent Featured pictures and Featured portals. These pages need to be kept cohesive and form a unit. Any new design should incorperate all of them.
- Portals. These are slipery slopes. Some portals have chosen colors arbitrarily, others (such as those for countries using the colors of the nation's flag) have not. It's best to propose a change on the portal's talk page (the main one, not one for the subpages) first.
- List of topic lists, Portal:Browse, Wikipedia:Browse, List of glossaries, and Wikipedia:Browse by overview. These pages are also a cohesive unit.
- Any other pages that seem similar to those listed above. Use common sense, and obey the spirit, not the letter, of this guideline.
What is it not for?
This guideline does not apply to most pages and some types of edits. The following remain unrestricted.
- Articles. Perhaps most importantly, this guidelines does not apply to articles. Since page formatting for articles is less complicated and much more standardized, we encourage users to format articles, as layed out in the Manual of Style.
- All other pages. Pages that are used for discussion, policy, guideline, userpages (if it's your own) or the like are fine.
- Content edits. Changing text, even in a page that this guideline applies to, is fine. Major changes—cuch as a complete rewrite—should be discussed first. But most things, such as adding a sentace or correcting a typo, are fine.
- Consensus edits. This guideline does not bar you from editing the page layout, just editing it without discussing it with other users. If you have talked about it on the talk page and the community approves, go for it. Always build on the existing page design. Don't compromise the work of others.