插件地址：
1.Wordpress Related Posts
https://wordpress.org/plugins/wordpress-23-related-posts-plugin
2.设置样式
在高级设置里面勾上Enable Themes*
选择：Plain (your own css)
勾上Enable custom CSS
CSS如下：
.related_post_title {
font-size: 1.3rem !important;
font-weight: 400 !important;
margin-top: 35px;
}
ul.related_post {
list-style:none;
margin-left: 0em !important;
}
ul.related_post li {
line-height: 2;
}
ul.related_post li a {
}
ul.related_post li img {
}