RewriteEngine On

# force https
RewriteCond %{HTTPS}  !=on
RewriteRule ^/?(.*) https://%{SERVER_NAME}/$1 [R,L]

# remove trailing slash
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)/$ /$1 [L,R] # R=301

# SPA mode
RewriteBase /
RewriteRule ^200\.html$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /200.html [L]

# redirect not found urls to .html files
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^./]+)/?$ $1.html [QSA]