What is the difference between em, rem, and px units?

The difference between em, rem, and px units as follows: em: A relative unit based on the font size of the parent element, causing the size to scale accordingly. rem: A unit that scales relative to the font size of the root element (), offering consistent sizing across the entire document. px (Pixels): A fixed unit of measurement that doesn’t adjust based on other elements or settings. For example, .text { font-size: 1.5em; } /* 1.5 times the parent element's font size */ .root { font-size: 16px; } .text2 { font-size: 2rem; } /* 32px if the root element's font size is 16px */