Dear weipeng liu,
If you are hidding top bar from customizer than banner height is manipulated with 110px which is coming from customizer.php template. This is driven by jquery.
YOu can see this code here on customizer.php template [ theme folder -> inc -> customizer.php]
if (top_activated == 1) {
$('#la-banner').css({"min-height" : "110px"});
}
Note: Please use child theme to customize the parent template, otherwise your changes will lost on theme update.
Thanks
