clicking on ".ar__close" removes class "open" on ".ar__modal"
clicking on ".search_btn" toggles class "open" on "#search_md"
clicking on "#category_dd_btn" toggles class "open" on "#category_dd"
clicking on ".dp__backdrop" removes class "open" on "#category_dd"
clicking on "#category_dd__md_btn" toggles class "open" on "#category_dd_mb"
clicking on ".dp__backdrop" removes class "open" on "#category_dd_mb"
clicking on ".nav__dp" toggles class "hidden" on "#nav_menu"
