Given the abundance of div elements in modern HTML, a CSS rule to set padding in all of them can only make sense in an unlikely minority of abnormally simple an

Given the abundance of div elements in modern HTML, a CSS rule to set padding in all of them can only make sense in an unlikely minority of abnormally simple and constrained pages. Setting a huge, fixed 15em padding is also highly suspect. You need to "fight" only in poorly designed systems; UI elements can pretend to have a hierarchical namespace and avoid all interference with other components, and pages can be designed systematically (e.g. box-sizing border-box vs. content-box, padding vs. margin, flex...) to simplify CSS rules. div.arbitrary-ui-library-prefix-radio-button-group { padding:0.5em; border: 0.1em dotted rgba(0,0,0,0.3); } div.arbitrary-ui-library-prefix-huge-padded-box-container { padding:15em; }