Try merge: All tests passed, ready to release v3.0

[lingering126]

Hi guys,

I have fixed some bugs of displaying and did some modifies of intro page. All tests have passed. Please check branch "try merge".

Everyone can run pip install -r requirements.txt , python app.py to run the app, and then run python -m unittest discover -s tests to test.

If you have any ideas, please comment below. Cheers!🙌

[jacky-zq-woo]

Great job Yi! Thanks for debugging