Definition
Rem is a relative unit of measurement in web design that is used in a similar way to em, but is always relative to the font size of the root element (usually the element). This means that 1rem always corresponds to the font size defined in the root element, regardless of the font size of the parent element. For example, if the font size of the root element is set to 16 pixels, 1rem always corresponds to 16 pixels.
The advantage of rem is that it enables consistent scaling throughout the layout, as all dimensions are in relation to the global font size. This makes the use of rem particularly useful if you want a design that is consistent and easy to control. Since all dimensions refer to the same base, working with rem is often easier and more predictable than with em, especially with deeply nested elements.
Related topics
- em: Unit of measurement