nginx.conf

server {
    listen 80;
    listen [::]:80;
    server_name localhost;

    root /usr/share/nginx/html;
    index index.html index.htm;

    # Security headers to enforce HTTPS
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
    add_header Content-Security-Policy "upgrade-insecure-requests" always;
    add_header X-Content-Type-Options "nosniff" always;
    add_header X-Frame-Options "SAMEORIGIN" always;

    gzip on;
    gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

    location / {
        try_files $uri $uri/ $uri.html /index.html;
    }

    error_page 404 /404.html;
    location = /404.html {
        internal;
    }
}