.htaccess

<IfModule headers_module>
    Header set X-Frame-Options SAMEORIGIN
</IfModule>
<IfModule rewrite_module>
    RewriteEngine On

    # Block access to storing directories
    RewriteRule (^|/)\~ - [F]

    # Access file without extension
    RewriteCond %{DOCUMENT_ROOT}/$1\.php -f
    RewriteRule ^(.+?)/?$ /$1.php [L]
    # Remove index file
    RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\s/(|.*/)index\.php($|\s|\?) [OR]
    # Remove file extension
    RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\s/(.*)\.php($|\s|\?)
    RewriteRule (^|.+) /%1 [R=301,L]

    # Web Manifest
    RewriteRule ^manifest.webmanifest$ manifest.php [L]

    # Filename-based cache busting
    RewriteRule ^(.+)-(\d{1,10}+).css$ $1.min.css [L]
    RewriteRule ^serviceworker$ serviceworker.php [L]

    # URL rewrite and secure directories
    RewriteCond %{THE_REQUEST} \s/+(\S+)
    RewriteRule ^achieve([^\.css$].*)?$ achieve.php?url=%1 [B,L]

    RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} !-f
    RewriteCond %{THE_REQUEST} \s/+(\S+)
    RewriteRule (.*) index.php?i=%1 [B,L]
</IfModule>