Hi there!
Thanks for your query.
Are you using a predefined header there?
However, please use the following code in your custom CSS:
#sp-bottom .sp-module, #sp-footer .sp-module {
text-align: center;
}
@media (max-width: 991px){
#sp-logo {
width: 83%;
}
#sp-menu {
width: 17%;
}
}
Hope this will serve your perpose for now!
Note: Path towards custom CSS(Joomla 3): Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.
Best Regards