server {
    listen 80;
    server_name xxx.com;

    location / {
        # 默认PC端访问内容
        root    "/var/www/public";

        # 如果是手机移动端访问内容
        if ($http_user_agent ~* "(mobile|iphone|ipad|android)") {
            root    "/var/www/mobile";
        }

        index index.html index.php;
    }
}