Content-box / border-box


Is there one I should use over the other or is it a personal preference/ situational choice?


It’s a technical choice, not a personal preference. When tightness of fit is not a concern then the border can be outside of the content box, but if the size is critical for the right fit, then the border should go inside the content box.




In the above, on the left the border is outside of the content box, on the right the border is inside content box.