function resize () {
    const baseFontSize = 16
    const windowWidth = document.documentElement.clientWidth;
    const newVal = Math.round((windowWidth / 1920) * baseFontSize)
    document.documentElement.style.fontSize = `${newVal}px`;
}
resize() //先调用一次，适配初次加载屏幕大小
window.addEventListener('resize', resize);  //挂载窗口大小事件