starter-academic navigation bar collapse in mobile view cannot be clicked

[yixinliu320]

I have not changed anything from the navbar.html.

Everything runs well when I view my website in local. After I publish the website on github, something wrong happens. Everything is fine when I view it from my macbook. However, if the screen become smaller, for example view it on the phone, the collapse navigation icon cannot be clicked. The dropdown item does not show.

Everything from my web is fine, but this button cannot be clicked.

It supposed to be clickable, and the dropdown menu should be appeared like this in local:

Is there any bug in the navbar.html? Or I need to modify other files.