Hi there!

Thanks for your query.

Please use the following code in your custom CSS:

#sp-header .row{
display: flex;
}
#sp-menu2 {
flex: auto;
}

Hope this will solve the issue for you.

Note: Path towards custom CSS: Extensions>Templates>Styles> Click on your current default template name then choose Template Options. Then find custom CSS within the custom code.

Best Regards