<form class="input-group" action="<?php echo esc_url(home_url()) ?>" method="get">
	<input type="text" class="form-control" placeholder="<?php rst_the_translate('Search for...','translation_search_for') ?>" name="s">
	<span class="input-group-btn">
		<button class="btn btn-default"><i class="fa fa-search"></i></button>
	</span>
</form>	