AOS is not defined mean and how i can i fix it the code os in description

Question

https://code.sololearn.com/WvaZsdl5D8lb/?ref=app

Answer 1

1. You had not used the cdn link.(cdn provided in its website)
2. Use semicolon after the brackets.
3. Write a proper html structure.

Your error will be solved.

Answer 2

Please formatting your html in a proper way.
https://code.sololearn.com/WSrMf1M4NbB0/?ref=app

Answer 3

Thank so much with your help i have fix my error
And created my new code
= https://code.sololearn.com/WEME4Wge8U35/?ref=app