Nginx Typecho 自定义 404 页面不适用于不存在的 PHP 文件（摆弄了两天快哭了）

访问某些文件类型不存在的文件，如xxx.html、xxx.log、xxx.txt等，能够显示主题自定义404内容，但是访问一个不存在的PHP、css、js等文件，还是返回nginx默认的404页面。这是怎么回事？

下面是我的配置：
nginx.conf
========
server
{
listen xx.xx.xx.xx:80;
#listen [::]:80;
server_name xx.com www.xx.com;
index index.html index.htm index.php default.html default.htm default.php;
root /home/wwwroot/vhosts/xx;

include typecho.conf;

location ~ [^/]\.php(/|$)

{
fastcgi_pass unix:/tmp/php-cgi.sock;
fastcgi_index index.php;
include fastcgi.conf;
include pathinfo.conf;
}

location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$
{
expires 30d;
}

location ~ .*\.(js|css)?$
{
expires 12h;
}

}
-------------------------------------------------------------------------
typecho.conf
========
location / {
index index.html index.php;
if (-e $request_filename/index.html){
rewrite (.*) $1/index.html break;
}
if (-e $request_filename/index.php){
rewrite (.*) $1/index.php;
}
if (!-e $request_filename){
rewrite (.*) /index.php;
}
}
-------------------------------------------------------------------------
pathinfo.conf
========
fastcgi_split_path_info ^(.+?\.php)(/.*)$;
set $path_info $fastcgi_path_info;
fastcgi_param PATH_INFO $path_info;
try_files $fastcgi_script_name = 404;