ps -fA | grep "python3\|http.server" | awk -F ' ' '{print $2}' | head -1
Use to get process ID of existing python server, if it exists. If such a process does not exist, it will simply output the process of this command.
Then use kill <process-id> to kill process.
The reason why pages might look different using http versus using https might be due to the website not loading the stylesheets (CSS). In my case, my stylesheet used a Yahoo API over http which was not allowed.
Link: https://teamtreehouse.com/community/http-vs-https-same-page-looks-different