Need help with CSS horizontal sub-category menu

I’m customizing a theme to display a list of sub-categories on a portfolio page.

On the following page – https://www.amcreativestudio.com – I’d like to display the categories “Magazine, Corporate, Fashion, etc.) horizontally next to the “Web design categories” text.

I’m using #submenu li{ display:inline;}

Do I also need to use #submenu li{ list-type: none;}` ?

Thanks!