为什么 Google PageSpeed Insight 会将按钮（带有悬停效果）作为动画？

根据https://developers.google.com/web/fundamentals/performance/rendering/stick-to-compositor-only-properties-and-manage-layer-count，您必须删除按钮的过渡效果。

a.btn, a.button, .inner-page-contact form button, .testimonial-form-holder button, input[type="button"], input[type="reset"], input[type="submit"] {

    /* -webkit-transition: all 0.2s ease-in-out;
    -moz-transition: all 0.2s ease-in-out;
    -o-transition: all 0.2s ease-in-out;
    -ms-transition: all 0.2s ease-in-out;
    transition: all 0.2s ease-in-out; */