Header Menu Icon Issue - Mobile device

Hi there,

I just finished the product landing page project, but I am having an issue.
On mobile device, I have a burger menu icon appearing, but the behavior is quite strange when you click on it.
I need to click twice on it before menu appearing, icon moves slightly and after that, the header isn’t fixed anymore.So you need to refresh the page. It will be much clearer if you have a live test.
I deployed the website here and my code is hosted on github

Thanks so much in advance for your help fixing this issue !
And other comments are also welcome :wink: