Main Content Sidebar Grid-gap Width Setting Interface

Right now, to control the gap between the sidebar and main content you have to use custom css or put it in your child theme's CSS. I'd like to see an interface to edit that gap. Frankly, I'd like to see a site-wide global default layout that includes a sidebar grid gap width setting under Post/Pages Layout -> Global Default Layout -> Sidebar Grid Gap and then also be allowed to change it more granularly under Post/Pages Layout -> Page /Single Post/Achive layout -> Sidebar Grid Gap. If there is no sidebar selected, the capability disappears from the UI.