.navigation-search input[type="search"] {
opacity: 1;
font-size: 36px;
text-transform: uppercase;
font-weight: 900;
text-align: center;
}
If the logo size was changed from GeneratePress default, use this code to expand the container height:
body nav:not(.is_stuck) .navigation-search input[type="search"] {
height: 90px;
}