A yellow light means that you need to be a registered member that no longer has the "new editor" tag next to their name on their user page in order to edit that page. The "new editor" tag is removed 4 days after you join the wiki.
红灯所在页面的编辑权限仅限于管理员。A page is typically given this level of protection because it is considered to be complete.
Note that while user pages are not typically protected, it is generally considered to be polite to obtain that user's permission before editing their personal page. If you have any questions, please ask one of the staff members for assistance.