1
HTML/CSSBeginner#html#semantics
Some newer CSS features require vendor prefixes (-webkit-, -moz-) for partial browser support. Autoprefixer is a PostCSS plugin that automatically adds necessary prefixes based on a target browser list (browserslist), so developers write standard CSS without manually tracking prefix requirements.
/* You write: */
.box { display: flex; user-select: none; }
/* Autoprefixer outputs: */
.box { display: -webkit-box; display: -ms-flexbox; display: flex; -webkit-user-select: none; user-select: none; }