<section>标签背景固定图像在标题上重叠

Question

section {
    position: relative;
    width: 100%;
    height: auto;
    min-height: 500px;
    padding: 40px 0;
    color: #333;
    font-size: 14px;
    background-image: url("a.jpg");
    background-repeat: no-repeat;
    background-attachment: fixed;
    background-position: center top;
    background-origin: content-box;
}

我的css代码，但背景从网站开头而不是标题下开始？我该如何解决问题

summary of problem