How to remove hamburger menu icon on top of mobile page

Hi, I made a very simple website (it’s still under construction). It looks good on the website but for some reason, there is this hamburger menu icon on mobile version. I need to remove it because there is nothing on the menu right now. I tried some CSS custom thing suggested in previous thread but it didn’t work. Please let me know how to get rid of the hamburger menu icon on top of my mobile website page. Thanks.