Hi,
You have the following custom CSS rule active, which removes the search icon on mobile devices:
@media screen and (max-width: 1050px)
.site-navigation #search-icon {
display: none;
}
This hides the search container menu element, looks like it’s a custom theme rule of some sort. If you remove that, the search icon will be visible again. If you don’t know where it’s coming from, you can either ask the theme developer, or try using this rule as well to override that:
@media screen and (max-width: 1050px) {
.site-navigation #search-icon {
display: block !important;
}
}