Ask HN: Idea for web-design website / forum

I'm considering creating a simple forum where people can share web design ideas. The concept is a little different than anything I've come across, so please let me know if it exists so I don't end up trying to reinvent what's already out there. I imagine this site would be similar in concept to HN in the sense that people would begin new topics, and then based on community interest / engagement perhaps those topics would either slide up or down on the front page. The main difference is, the "topics" people would provide would be screenshots of particular elements from existing websites, and the forum would be where people would share their insights / styles / techniques for accomplishing that same design. For example, a user might submit a new topic which shows a screenshot of Twitter's website, and wants to share their techniques for how to create (using HTML / CSS / JS / Sass / Less / etc) the functionality and behavior of the header. Within the forum, people would engage in conversation about, or share their own techniques, or debate whether or why a particular technique is not considered best practices or should / should not be used, etc. I really think something like this would help take the online dialogue about web design to another level for a couple reasons, but mainly because it focuses attention on specific cases and isolates particular components of the design of a web page. There's probably no reason this kind of thing couldn't be done on an existing forum website, by linking to sites like jsfiddle.net, but I imagine there are probably some customizations that could be done to a common forum format that would fit / streamline this idea a little more cleanly.