Fix Tutorials.Structure (ja) header overlaying breadcrumbs and lang selector

Same as #415
Fix Tutorials.Set (ja) header overlaying breadcrumbs and lang selector

Same as #415
Fix Tutorials.Map (ja) header overlaying breadcrumbs and lang selector
Fix Tutorials.Streams (en) header overlaying breadcrumbs and lang selector
Merge pull request #416 from dsheets/patch-5

Fix Tutorials.Structure (ja) header overlaying breadcrumbs and lang selector