The default theme of shiny UI is very readable and modern. However, I often have real-estate issues with forms, as I cannot put all the UI components that I need on a single screen (especially in the vertical dimension) even when I break things up in tabpanels. The themes from the shinytheme package provide some alternative color / font combos, but do not seem to change (much?) the size of the UI components nor the margins applying around components.
Is there a way to control margins and size of UI components (beyond the width) to make a more compact (crowded?) looking app?