I’m using a custom child theme of Xi and I’m trying to get the Site title and subtitle to be aligned to the right of the logo image, but don’t really know where in the CSS stylesheet I can change that. And hopes are that on small screens it still alignes centered below the logo image. Any tips or clues to get me started?
Most of the layout is defined in \extend\layouts\responsive-1.css
And you are right to worry what happens on smaller devices. This layout css file also includes some media-queries that adjust layout for different devices. So if you do alter the layout on the default desktop size, you may need to add some media queries to make it right again on smaller devices.
The other things to consider – most users of this theme have the site title/desc turned off (in theme options). You could then incorporate a title in a custom logo, which is easier to handle.