Chat App Illustration Master using flex display and positioning

This challenge took a lot of time and i think i have made it look complex. If anyone can review and suggest me the areas I need to work on will be helpful.

p.s. The background color is different from the challenge given.

And also when I open my site it looks fine, but in design comparision the "type a message" section goes out of "div" element. Can someone let me know the reason?

Now planning to go ahead with Javascript learning, so would love to know which areas i need to improve before moving ahead.