Hi there,
try this CSS – it shortens the width and places the search below the nav, i added the extra rules for where you can change the colors.
.navigation-search {
height: 30px;
bottom: auto;
top: 115%;
}
.navigation-search .search-field {
width: 50%;
float: right;
min-width: 300px;
}
.navigation-search input:hover,
.navigation-search input:focus {
opacity: 1
};
.navigation-search input[type="search"],
.navigation-search input[type="search"]:active {
color: #ffffff;
/* Change text color */
background-color: #ffffff;
/* change search field background */
border: 1px solid #dddddd;
/* add border color */
}