Learn how to close list items with JavaScript.
Read on how to do it in this tutorial: https://www.w3schools.com/howto/howto_js_close_list_items.asp
Closable List Items
Click on the "x" symbol to the right of the list item to close/hide it.
Try it yourself here: https://www.w3schools.com/howto/tryit.asp?filename=tryhow_js_close_list_items