!function(n, e) {
var t = n.documentElement,
i = "orientationchange" in window ? "orientationchange": "resize",
d = function() {
var n = t.clientWidth;
n && (t.style.fontSize = (n > 750 ? 750 : n) / 750 * 100 + "px")
};
n.addEventListener && (e.addEventListener(i, d, !1), d(), n.addEventListener("DOMContentLoaded", d, !1))
} (document, window);
设计稿 750 ,那么尺寸100px 就是1rem