Submenu box size

[pixle123]

Hello,

I run prestashop 1.7.5.0 / Template: Lingerie & Adult - Fashion SexShop Clothes, Toys, Love Template

I would like to change the submenu size to smaller. 

This:

To this:

Thanks

[pixle123]

I would like to add something like this through custom css:

#header .header-top {
    margin-left: 200px;
    margin-right: 200px;
    margin-top: 20px;
}

It does not work if I add it to / web / themes / mytheme/ assets / css / custom.css

What should be changed to get it working?

Thanks

Edited January 13, 2020 by pixle123 (see edit history)