html < html lang = " en " > < head > < meta charset = " UTF-8 " > < meta http-equiv = " X-UA-Compatible " content = " ie=edge " > < title > test </ title > < script src = " lib/flexible_css.js,flexible.js " > </ script > < link rel = " stylesheet " href = " css/css.css " > </ head > < body > < div class = " a " > </ div > < div class = " b " > </ div > </ body > </ html > less(vscode使用easy less转换) // 设计稿宽度 单位px 如果是750 请使用375宽度的手机开发 @DesignWidth : 750 ; @BaseFontSize : @DesignWidth /10 ; // 函数式 // . rem ( width,100 ) ; . rem ( @name , @px ) { @ { name } : unit ( @px / @BaseFontSize , rem ) ; }