Nightfirecat questions

Nightfirecat answers

• Is chaining CSS classes in such a way valid?
• Background image color changes firefox/chrome
• Making an unordered list stretch horizontally so as to always fill up a div
• What's the appropriate HTTP response for invalid data submitted by the user?
• Affecting div:hover with another div [duplicate]
• match until a certain pattern using regex
• Is it possible to modify the $_SESSION variable?
• How is the meta viewport tag used, and what does it do?
• CSS container div not getting height
• Scalable div larger than window