search box in header

i used to have a search box in my header, just to the right of my logo. after the recent update it has disappeared. does anyone know how to get it back?

website url is https://www.hhhsupply.com/

custom CSS has this in it, which used to create a search bar:

.header-search {display:none;}

@media screen and (min-width: 600px) {
	.header-search {
		display:block;
		float:right;
		position:relative;
		margin-top:-40px;
	}
}