I am using Debut template. The drop down menu of the collections is currently displayed as 5 columns/two rows. It doesn’t look organized either. I want to change to using a single-column/multiple rows layout, instead of several columns.
How can I do that? Thank you!
Sorry you are facing this issue, it would be my pleasure to help you.
Welcome to the Shopify community! 
Thanks for your good question.
Please share your site URL,
I will check out the issue and provide you a solution here.
https://mignon-ballet.myshopify.com/
This is the site. Thank you!
https://mignon-ballet.myshopify.com/
This is the site. Thank you!
thanks for url but your store password protect