Color and language of Search bar in Header

How do put an outline on the search bar in the header? It is white and I cannot figure out how to change it. My header background is white and if I change that then it will show a box outline the search (see screenshot) but I need it to stay white because of my logo. I would also like the “search” to be black–the color is too hard to see.
Also is there a way to change the terminology to “Search the directory” Instead of just Search?

I tried to change it here but it did not work.
/*** SEARCH BOX ***/
.wlt_searchbox { margin-right:0px; padding:10px; margin-top:0px; margin-top:10px; }
.wlt_button_search i:hover { color:#000; }
.wlt_searchbox .wlt_button_search { margin-top:10px; margin-right:10px; color:#fff; }
.wlt_searchbox input { background: #000; padding:10px;

Thanks!