"Edge LULW" I know, but I feel like this is an issue that should be addressed regardless.
On other browsers (for example, I'm currently using Chrome) it shows the expansion watermark next to the card. However, on Edge it's just a square of colour, as can be seen below.
On Chrome:

On Edge:


In addition, while I can type out comments, forum posts and deck descriptions, I am unable to submit whatever it is I am typing. Finally, hovering over the page dropdown lists works on Chrome, but not on Edge.
On Chrome:

(very responsive dropdown menu)
On Edge:
(no dropdown menu)
Now, I realise that this is a new website and it's going to have it's kinks, and I will admit that I would have never been able to make a website even remotely close to this. However, I still think that it's important for these issues to at least be brought into the limelight, because if nobody talks about a problem then it won't be solved.