RewriteEngine On

# Jangan rewrite file/folder yang benar-benar ada
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]

# URL: /book/jadwal
RewriteRule ^book/([A-Za-z0-9_-]+)/?$ viewer.php?book=$1 [L,QSA]

# Halaman utama
DirectoryIndex index.php

ErrorDocument 404 /404.php