const baseWidth = 1920 // 设计图宽度
const baseSize = 10 //  rem 比例
const doc = document.documentElement
function refreshRem() {
   const width = doc.getBoundingClientRect().width
   doc.style.fontSize = baseSize * Math.min(width / baseWidth, 1) + "px"
}
refreshRem()
window.addEventListener("resize", refreshRem)