How can I make the dropdown (text/items)  menu do be NOTY transparent but to keep the menu transparent?

And also,. how to round the corners of the menu and dropdown so its not square?
I would like something like this see screenshot

Hi Andrew, it works, with the rounded corner thank you!

1: The background dont work to be solid color, I have the following CSS in the theme.

2: Is it any chance to get the kind of "arrow" like the other menu have on the screen shot.

/*TO UNCLEAR WHAT IT DOES */
body #header-outer, body[data-header-color="dark"] #header-outer {
    background: transparent;
}
/*TO UNCLEAR WHAT IT DOES */

/*TO MAKE MENU POPDOWN ROUNDED */
#search-outer .ui-widget-content, body:not([data-header-format="left-header"]) #top .sf-menu li ul, #top nav > ul > .megamenu > .sub-menu, body #top nav > ul > .megamenu > .sub-menu > li > a, #header-outer .widget_shopping_cart .cart_list a, #header-secondary-outer ul ul li a, #header-outer .widget_shopping_cart .cart_list li, .woocommerce .cart-notification, #header-outer .widget_shopping_cart_content {
    background-color: #ffffff;
    border-radius: 10px;
/*TO MAKE MENU POPDOWN ROUNDED */

Hi Again!

The dropdown opacity works like a charm.

The arrow dont work. See attached

Hi Andrew,  I would be fint with a down arrow but it still dont work.

Hi Andrew, Ahh okey. Well I sissunerstod you. Its fine, thank you so much!