nginx proxy_pass subdirectory for YACReader server

I am trying to hosting YACReader server to with nginx proxy_pass.
But I never got it done.
When I open , it can not get the resource files(like css and some picture files) correctly, the page always trying to get the resource files at:
e.g.:
I was configure nginx like this:
nginx.conf:

include /etc/nginx/modules-enabled/*.conf;

events {
worker_connections 768;
}

http {
sendfile on;

tcp_nopush on;
tcp_nodelay on;

keepalive_timeout 65;

types_hash_max_size 2048;

server_tokens off;

default_type application/octet-stream;

access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;

gzip on;

client_max_body_size 100M;

include /etc/nginx/mime.types;

include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}

/etc/nginx/sites-enabled/homepage.conf:
Reference: www.yacreader.com/forum/support-ios/1545...nginx-reversed-proxy

server {
server_name 192.168.8.100 127.0.0.1;

listen 80;
listen [::]:80;
listen 443 ssl;
listen [::]:443 ssl;

# ssl on;

ssl_certificate /opt/homeserverCA/ca.crt;
ssl_certificate_key /opt/homeserverCA/ca.key.unsecure;

ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3;
ssl_ecdh_curve X25519:P-256:P-384:P-224:P-521;
ssl_ciphers 'EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH:ECDHE-RSA-AES128-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA128:DHE-RSA-AES128-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES128-GCM-SHA128:ECDHE-RSA-AES128-SHA384:ECDHE-RSA-AES128-SHA128:ECDHE-RSA-AES128-SHA:ECDHE-RSA-AES128-SHA:DHE-RSA-AES128-SHA128:DHE-RSA-AES128-SHA128:DHE-RSA-AES128-SHA:DHE-RSA-AES128-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA384:AES128-GCM-SHA128:AES128-SHA128:AES128-SHA128:AES128-SHA:AES128-SHA:DES-CBC3-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4';
ssl_prefer_server_ciphers on;

location = /yacserver {
return 301 /yacserver/;
}

location /yacserver/ {
proxy_pass http://127.0.0.1:18004/;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
proxy_http_version 1.1;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

# If you want to log the remote port of the image senders, you'll need that
proxy_set_header X-Remote-Port $remote_port;
proxy_set_header X-Forwarded-Proto $scheme;

# We expect the downsteam servers to redirect to the right hostname, so don't do any rewrites here.
proxy_redirect off;
}
}

How can I get it done, Thanks.