diff --git a/VERSION b/VERSION
index 9435145..5ca0603 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-1.0.87
+1.0.88
diff --git a/classes/Document.class.php b/classes/Document.class.php
index 14746b9..3bb7387 100644
--- a/classes/Document.class.php
+++ b/classes/Document.class.php
@@ -34,86 +34,86 @@
 
 final class Document{
 
-	protected string $ID;
-	protected string $PATH;
-	protected string $URL;
-	protected string $DIR;
-	protected string $TITLE;
-	protected string $VERSION;
-	protected ?string $FILE;
-	protected ?int $TIMESTAMP;
-
-  /**
-   * Constructor
-   *
-   * @param string $id Document ID (examples: homepage, samples/typography )
-   */
-	public function __construct(string $id){
-		// definitions
-		$this->ID=$id;
-		$this->PATH=PATH."datasets/documents/".$this->ID;
-		$this->URL=URL.$this->ID;
-		$this->DIR=ROOT.$this->PATH."/";
-		$this->TITLE=self::getTitle($this->ID);
-		$this->VERSION=(strlen($_GET['version']??'')?$_GET['version']:"latest");
-		$this->FILE=$this->DIR."content.md";
-		$this->TIMESTAMP=null;
-		// check if file exist
-		if(!file_exists($this->FILE)){$this->FILE=null;}
-		if(file_exists($this->FILE ?? '')){$this->TIMESTAMP=filemtime($this->FILE);}
-	}
-
-	/**
-	 * Get property
-	 *
-	 * @param string $property Property name
-	 * @return mixed Property value
-	 */
-	public function __get(string $property){return $this->{$property};}
-
-	/**
-	 * Export all properties
-	 *
-	 * @return array of properties
-	 */
-	public function export():array{
-		$properties_array=array();
-		foreach($this as $key => $value){
-			$properties_array[$key]=$value;
-		}
-		return $properties_array;
-	}
-
-	/**
-	 * Load document content form source file
-	 *
-	 * @param string $paths Format for paths [WEB|FS]
-	 * @return string Content markdown source code
-	 */
-	public function loadContent($paths="WEB"):string{
-		// check for specific version
-		if($this->VERSION!=="latest"){
-			$file_path=$this->DIR."versions/".$this->VERSION.".md";
-			// check if exists or fallback to default file
-			if(!file_exists($file_path)){$file_path=$this->FILE ?? '';}
-		}else{$file_path=$this->FILE ?? '';}
-		// check if file exist
-		if(!file_exists($file_path)){return false;}
-		// load content from file
-		$content=file_get_contents($file_path);
-		// replace path placeholders
-		switch(strtoupper(trim($paths))){
-			case "WEB":
+    protected string $ID;
+    protected string $PATH;
+    protected string $URL;
+    protected string $DIR;
+    protected string $TITLE;
+    protected string $VERSION;
+    protected ?string $FILE;
+    protected ?int $TIMESTAMP;
+
+    /**
+     * Constructor
+     *
+     * @param string $id Document ID (examples: homepage, samples/typography )
+     */
+    public function __construct(string $id){
+        // definitions
+        $this->ID=$id;
+        $this->PATH=PATH."datasets/documents/".$this->ID;
+        $this->URL=URL.$this->ID;
+        $this->DIR=ROOT.$this->PATH."/";
+        $this->TITLE=self::getTitle($this->ID);
+        $this->VERSION=(strlen($_GET['version']??'')?$_GET['version']:"latest");
+        $this->FILE=$this->DIR."content.md";
+        $this->TIMESTAMP=null;
+        // check if file exist
+        if(!file_exists($this->FILE)){$this->FILE=null;}
+        if(file_exists($this->FILE ?? '')){$this->TIMESTAMP=filemtime($this->FILE);}
+    }
+
+    /**
+     * Get property
+     *
+     * @param string $property Property name
+     * @return mixed Property value
+     */
+    public function __get(string $property){return $this->{$property};}
+
+    /**
+     * Export all properties
+     *
+     * @return array of properties
+     */
+    public function export():array{
+        $properties_array=array();
+        foreach($this as $key => $value){
+            $properties_array[$key]=$value;
+        }
+        return $properties_array;
+    }
+
+    /**
+     * Load document content form source file
+     *
+     * @param string $paths Format for paths [WEB|FS]
+     * @return string Content markdown source code
+     */
+    public function loadContent($paths="WEB"):string{
+        // check for specific version
+        if($this->VERSION!=="latest"){
+            $file_path=$this->DIR."versions/".$this->VERSION.".md";
+            // check if exists or fallback to default file
+            if(!file_exists($file_path)){$file_path=$this->FILE ?? '';}
+        }else{$file_path=$this->FILE ?? '';}
+        // check if file exist
+        if(!file_exists($file_path)){return false;}
+        // load content from file
+        $content=file_get_contents($file_path);
+        // replace path placeholders
+        switch(strtoupper(trim($paths))){
+            case "WEB":
                 // I also escape the script tags to prevent XSS.
                 $source=str_replace(array("{{APP_PATH}}","{{DOC_PATH}}"),array(PATH,$this->PATH."/"),$content);
                 $source = $this->sanitizeHtml($source);
                 break;
-			case "FS":$source=str_replace(array("{{APP_PATH}}","{{DOC_PATH}}"),array(URL,$this->DIR."/"),$content);break;
-			default:$source=str_replace(array("{{APP_PATH}}","{{DOC_PATH}}"),"",$content);
-		}
-		// return
-		return $source;
-	}
+            case "FS":$source=str_replace(array("{{APP_PATH}}","{{DOC_PATH}}"),array(URL,$this->DIR."/"),$content);break;
+            default:$source=str_replace(array("{{APP_PATH}}","{{DOC_PATH}}"),"",$content);
+        }
+        // return
+        return $source;
+    }
 
     /**
      * If I find an event in the code, I sanitize some dangerous html tags and attributes by replacing some character with the corresponding escape code, so that the event handler is not executed, but the code is displayed instead.
@@ -220,10 +220,7 @@ private static function isDangerousUrl($url, $attrName) {
         }
         if (preg_match('/^data\s*:/i', $url)) {
             // Allow safe base64 image MIME types in src attributes only
-            if ($attrName === 'src' && preg_match(
-                '#^data:image/(png|jpeg|jpg|gif|webp)\s*;\s*base64,[A-Za-z0-9+/=]+$#i',
-                $url
-            )) {
+            if ($attrName === 'src' && preg_match('#^data:image/(png|jpeg|jpg|gif|webp)\s*;\s*base64,[A-Za-z0-9+/=]+$#i', $url)) {
                 return false;
             }
             return true;
@@ -344,405 +341,406 @@ private static function iframeSrcAllowed($src, array $allowedHosts) {
         return in_array($host, $allowedHosts, true);
     }
 
-	/**
-	 * Document render
-	 *
-	 * @return string Document HTML source code
-	 */
-	public function render():string{
-		// load content from file and convert paths for web
-		$content=$this->loadContent("WEB");
-		// add content or if content is null add document title to source code
-		if($content!=false){$source=$content;}else{$source="# ".$this->TITLE."\n";}
-		// check for attachments
-		$attachments_array=$this->attachments();
-		if(count($attachments_array)){
-			// build attachments index
-			$source.="\n\n___\n";
-			// cycle all attachments
-			foreach($attachments_array as $attachment_fe){
-				$source.="- [".$attachment_fe->label."](".$attachment_fe->url.")\n";
-			}
-		}
-		// search for sub-documents
-		$sub_documents=Document::index($this->ID);
-		// check for elements
-		if(count($sub_documents)){
-			// build sub-documents index
-			$source.="\n\n___\n";
-			// cycle all elements
-			foreach($sub_documents as $sub_element_fe){
-				// add element list
-				//wdf_dump($sub_element_fe->url);
-				$source.="- [".$sub_element_fe->label."](".PATH.$sub_element_fe->url.")\n";
-				// search for sub-sub-documents
-				$sub_sub_documents=Document::index($sub_element_fe->url);
-				// cycle all sub-sub-documents
-				foreach($sub_sub_documents as $sub_sub_element_fe){
-					// add element list
-					$source.="\t- [".$sub_sub_element_fe->label."](".PATH.$sub_sub_element_fe->url.")\n";
-				}
-			}
-		}
-		// check for content or elements index
-		if(!$content && !count($sub_documents)){
-			// check for view mode
-			if(MODE=="view"){
-				// check for homepage
-				if($this->ID=='homepage'){
-					// welcome
-					$source="# Welcome\n";
-					$source.="This is your Wiki|Docs home page.\n\n";
-					// check for edit authorization
-					if(Session::getInstance()->autenticationLevel()==2){
-						// document can be created
-						$source.="Click the edit button to create this page!";
-					}
-				}else{
-					// document not found
-					$source="# Error 404\n";
-					$source.="We are sorry but the page you are looking for does not exist.\n\n";
-					// check for edit authorization
-					if(Session::getInstance()->autenticationLevel()==2){
-						// document can be created
-						$source.="Click the edit button to create this page!";
-					}
-				}
-			}
-		}
-		// return source code
-		return $source;
-	}
-
-	/**
-	 * Document images
-	 *
-	 * @return array of images
-	 */
-	public function images():array{
-		// definition
-		$images_array=array();
-		// check directory
-		if(is_dir($this->DIR)){
-			// scan directory for documents
-			$elements=scandir($this->DIR);
-			// cycle all elements
-			foreach($elements as $element_fe){
-				// skip directories
-				if(is_dir($this->DIR."/".$element_fe)){continue;}
-				$file_extension=explode(".",$element_fe);
-				// check extensions
-				if(!in_array(end($file_extension),array("png","gif","jpg","jpeg","svg"))){continue;}
-				// add element to documents array
-				$images_array[]=$element_fe;
-			}
-		}
-		// sort images
-		sort($images_array);
-		// return
-		return $images_array;
-	}
-
-	/**
-	 * Document attachments
-	 *
-	 * @return array of attachments
-	 */
-	public function attachments():array{
-		// definition
-		$attachments_array=array();
-		// check directory
-		if(is_dir($this->DIR)){
-			// scan directory for documents
-			$elements=scandir($this->DIR);
-			// cycle all elements
-			foreach($elements as $element_fe){
-				// skip directories
-				if(is_dir($this->DIR."/".$element_fe)){continue;}
-				$file_extension=explode(".",$element_fe);
-				// check extensions
-				if(!in_array(end($file_extension),array("pdf","txt","doc","docx","xls","xlsx","ppt","pptx"))){continue;}
-				// make element
-				$attachment=new stdClass();
-				$attachment->label=$element_fe;
-        $attachment->url=PATH."datasets/documents/".$this->ID."/".rawurlencode($element_fe);
-				// add element to documents array
-				$attachments_array[]=$attachment;
-			}
-		}
-		// sort attachments
-		sort($attachments_array);
-		// return
-		return $attachments_array;
-	}
-
-	/**
-	 * Document versions
-	 *
-	 * @return array of versions
-	 */
-	public function versions():array{
-		// definition
-		$versions_array=array();
-		// check directory
-		if(is_dir($this->DIR."/versions/")){
-			// scan directory for documents
-			$elements=scandir($this->DIR."/versions/");
-			// cycle all elements
-			foreach($elements as $element_fe){
-				// skip directories
-				if(is_dir($this->DIR."/versions/".$element_fe)){continue;}
-				$file_extension=explode(".",$element_fe);
-				// check extensions
-				if(end($file_extension)!=='md'){continue;}
-				// make element
-				$version=new stdClass();
-				$version->label=$element_fe;
-				$version->url=$this->URL."?version=".substr($element_fe,0,-3);
-				// add element to documents array
-				$versions_array[]=$version;
-			}
-		}
-		// sort versions
-		sort($versions_array);
-		// return
-		return $versions_array;
-	}
-
-	/**
-	 * Document hierarchy
-	 *
-	 * @return array of hierarchy links
-	 */
-	public function hierarchy():array{
-		// definition
-		$hierarchy_array=array();
-		// explode document path
-		$breadcrumbs=explode("/",$this->ID);
-		// cycle all segments
-		foreach($breadcrumbs as $index=>$breadcrumb){
-			// make path
-			$path=null;
-			foreach($breadcrumbs as $index_link=>$breadcumb_link){if($index_link<=$index){$path.="/".$breadcumb_link;}}
-			// build item
-			$item=new stdClass();
-			$item->label=$breadcrumb;
-			$item->path=substr($path,1);
-			// add item to hierarchy array
-			$hierarchy_array[]=$item;
-		}
-		// return
-		return $hierarchy_array;
-	}
-
-
-
-	/**
-	 * Document title
-	 *
-	 * @param string $document Document ID
-	 * @return string Document title
-	 */
-	static function getTitle(string $document):string{
-		$title='';
-		// make path
-		$content_path=DIR."datasets/documents/".$document."/content.md";
-		// load content line by line to find document title if exist
-		if(file_exists($content_path)){
-			$handle=fopen($content_path,"r");
-			while(!feof($handle)){
-				$line=fgets($handle);
-				if(substr($line,0,2)=="# "){
-					$title=trim(substr($line,1));
-					break;
-				}
-			}
-			fclose($handle);
-		}
-		if(!strlen($title)){
-			// make title by path
-			$hierarchy=explode("/",$document);
-			$title=ucwords(str_replace("-"," ",end($hierarchy)));
-		}
-		// return
-		return $title;
-	}
-
-	/**
-	 * Document Update Date
-	 *
-	 * @param string $document Document ID
-	 * @return integer Update Date
-	 */
-	static function getUpdateDate(string $document):string{
-		$date=0;
-		// make path
-		$content_path=DIR."datasets/documents/".$document."/content.md";
-		// load content line by line to find document title if exist
-		if(file_exists($content_path)){
-			$date=filemtime($content_path);
-		}
-		// return
-		return $date;
-	}
-
-	/**
-	 * Document list in path
-	 *
-	 * @param ?string $parent Parent Document ID
-	 * @return Document[] array of documents
-	 */
-	static function list(?string $parent=null):array{
-		$documents_array=array();
-		// check parameters
-		if(substr((string)$parent,-1)!="/"){$parent.="/";}
-		if($parent=="/"){$parent=null;}
-		// make directory full path
-		$directory_path=DIR."datasets/documents/".$parent;
-		// check for directory
-		if(is_dir($directory_path)){
-			// scan directory for documents
-			$elements=scandir($directory_path);
-			// cycle all elements
-			foreach($elements as $element_fe){
-				// skip versioning and files
-				if(in_array($element_fe,array(".","..","versions"))){continue;}
-				if(!is_dir($directory_path.$element_fe)){continue;}
-				// build directory
-				$document=new stdClass();
-				$document->id=$element_fe;
-				$document->path=$parent.$element_fe;
-				$document->url=URL.$document->path;
-				$document->dir=$directory_path.$element_fe;
-				// add element to documents array
-				$documents_array[]=$document;
-			}
-		}
-		// return
-		return $documents_array;
-	}
-
-
-	/**
-	 * Documents Index
-	 *
-	 * @param ?string $parent Parent document ID
-	 * @return Document[] array of Documents
-	 */
-	static function index(?string $parent=null):array{
-		// definitions
-		$index_array=array();
-		$documents_array=array();
-		// get document list
-		$directories_array=Document::list($parent);
-		// build documents array
-		if(count($directories_array)){
-			// cycle all documents
-			foreach($directories_array as $document_fe){
-				if($document_fe->id=="homepage"){continue;}
-				// definitions
-				$document_url=$parent."/".$document_fe->id;
-				$document_label=Document::getTitle($document_url);
-				// check document url
-				if(substr($document_url,0,1)=="/"){$document_url=substr($document_url,1);}
-				// add document to documents array
-				$documents_array[$document_url]=$document_label;
-			}
-		}
-		// sort document array by title
-		asort($documents_array, SORT_NATURAL);
-		// cycle all documents and build index array
-		foreach($documents_array as $url_fe=>$label_fe){
-			// build index element
-			$element=new stdClass();
-			$element->label=$label_fe;
-			$element->url=$url_fe;
-			// add element to index array
-			$index_array[]=$element;
-		}
-		// return
-		return $index_array;
-	}
-
-	/**
-	 * Documents search in path
-	 *
-	 * @param string $query String for search
-	 * @param ?string $parent Parent Document ID
-	 * @return array of results
-	 */
-	static function search(string $query,?string $parent=null):array{
-		// Decode HTML entities
-		$query = html_entity_decode($query);
-		// trim the query to remove leading and trailing spaces
-		$query = trim($query);
-		// return an empty array if the query is empty after trimming
-		if (empty($query)) {
-			return array();
-		}
-		// parse the query into phrases and individual words
-		preg_match_all('/"([^"]+)"|(\S+)/', $query, $matches);
-		$queries_array = array_filter(array_merge($matches[1], $matches[2]));
-		// tree to array
-		function tree_to_array(&$array,$parent=null){
-			foreach(Document::list($parent) as $dir_fe){
-				$array[]=$dir_fe->path;
-				tree_to_array($array,$dir_fe->path);
-			}
-		}
-		// definitions
-		$paths_array=array();
-		$matches_array=array();
-		// get all documents directories recursively
-		tree_to_array($paths_array,$parent);
-		//wdf_dump($paths_array);
-		// cycle all directories
-		foreach($paths_array as $path_fe){
-			// check if content file exist
-			if(file_exists(DIR."datasets/documents/".$path_fe."/content.md")){
-				// open file handle for read
-				$handle=fopen(DIR."datasets/documents/".$path_fe."/content.md","r");
-				if($handle){
-					while(!feof($handle)){
-						// get line in buffer
-						$buffer=fgets($handle);
-						// define a buffer id
-						$buffer_id=md5($buffer.rand());
-						// cycle all query words
-						foreach($queries_array as $query_fe){
-							// check for query word
-							if(stripos($buffer,$query_fe)!==false){
-								// escape buffer for security
-								$buffer=htmlspecialchars($buffer);
-								// highlight query word in buffer
-								$buffer=self::highlighting($query_fe,$buffer);
-								$matches_array[$path_fe][$buffer_id]=$buffer;
-								// skip current file after 3 matches
-								if(count($matches_array[$path_fe])>2){continue(3);}
-							}
-						}
-					}
-					fclose($handle);
-				}
-			}
-		}
-		return $matches_array;
-	}
-
-	private static function highlighting($search,$string){
-		$index=0;
-		$result="";
-		while($index<strlen($string)){
-			if(strtolower(substr($string,$index,strlen($search)))===strtolower($search)){
-				$result.="<mark>".substr($string,$index,strlen($search))."</mark>";
-				$index=$index+strlen($search);
-			}else{
-				$result.=substr($string,$index,1);
-				$index++;
-			}
-		}
-		return $result;
-	}
+    /**
+     * Document render
+     *
+     * @return string Document HTML source code
+     */
+    public function render():string{
+        // load content from file and convert paths for web
+        $content=$this->loadContent("WEB");
+        // add content or if content is null add document title to source code
+        if($content!=false){$source=$content;}else{$source="# ".$this->TITLE."\n";}
+        // check for attachments
+        $attachments_array=$this->attachments();
+        if(count($attachments_array)){
+            // build attachments index
+            $source.="\n\n___\n";
+            // cycle all attachments
+            foreach($attachments_array as $attachment_fe){
+                $source.="- [".$attachment_fe->label."](".$attachment_fe->url.")\n";
+            }
+        }
+        // search for sub-documents
+        $sub_documents=Document::index($this->ID);
+        // check for elements
+        if(count($sub_documents)){
+            // build sub-documents index
+            $source.="\n\n___\n";
+            // cycle all elements
+            foreach($sub_documents as $sub_element_fe){
+                // add element list
+                //wdf_dump($sub_element_fe->url);
+                $source.="- [".$sub_element_fe->label."](".PATH.$sub_element_fe->url.")\n";
+                // search for sub-sub-documents
+                $sub_sub_documents=Document::index($sub_element_fe->url);
+                // cycle all sub-sub-documents
+                foreach($sub_sub_documents as $sub_sub_element_fe){
+                    // add element list
+                    $source.="\t- [".$sub_sub_element_fe->label."](".PATH.$sub_sub_element_fe->url.")\n";
+                }
+            }
+        }
+        // check for content or elements index
+        if(!$content && !count($sub_documents)){
+            // check for view mode
+            if(MODE=="view"){
+                // check for homepage
+                if($this->ID=='homepage'){
+                    // welcome
+                    $source="# Welcome\n";
+                    $source.="This is your Wiki|Docs home page.\n\n";
+                    // check for edit authorization
+                    if(Session::getInstance()->autenticationLevel()==2){
+                        // document can be created
+                        $source.="Click the edit button to create this page!";
+                    }
+                }else{
+                    // document not found
+                    $source="# Error 404\n";
+                    $source.="We are sorry but the page you are looking for does not exist.\n\n";
+                    if(!headers_sent()){ http_response_code(404); }
+                    // check for edit authorization
+                    if(Session::getInstance()->autenticationLevel()==2){
+                        // document can be created
+                        $source.="Click the edit button to create this page!";
+                    }
+                }
+            }
+        }
+        // return source code
+        return $source;
+    }
+
+    /**
+     * Document images
+     *
+     * @return array of images
+     */
+    public function images():array{
+        // definition
+        $images_array=array();
+        // check directory
+        if(is_dir($this->DIR)){
+            // scan directory for documents
+            $elements=scandir($this->DIR);
+            // cycle all elements
+            foreach($elements as $element_fe){
+                // skip directories
+                if(is_dir($this->DIR."/".$element_fe)){continue;}
+                $file_extension=explode(".",$element_fe);
+                // check extensions
+                if(!in_array(end($file_extension),array("png","gif","jpg","jpeg","svg"))){continue;}
+                // add element to documents array
+                $images_array[]=$element_fe;
+            }
+        }
+        // sort images
+        sort($images_array);
+        // return
+        return $images_array;
+    }
+
+    /**
+     * Document attachments
+     *
+     * @return array of attachments
+     */
+    public function attachments():array{
+        // definition
+        $attachments_array=array();
+        // check directory
+        if(is_dir($this->DIR)){
+            // scan directory for documents
+            $elements=scandir($this->DIR);
+            // cycle all elements
+            foreach($elements as $element_fe){
+                // skip directories
+                if(is_dir($this->DIR."/".$element_fe)){continue;}
+                $file_extension=explode(".",$element_fe);
+                // check extensions
+                if(!in_array(end($file_extension),array("pdf","txt","doc","docx","xls","xlsx","ppt","pptx"))){continue;}
+                // make element
+                $attachment=new stdClass();
+                $attachment->label=$element_fe;
+                $attachment->url=PATH."datasets/documents/".$this->ID."/".rawurlencode($element_fe);
+                // add element to documents array
+                $attachments_array[]=$attachment;
+            }
+        }
+        // sort attachments
+        sort($attachments_array);
+        // return
+        return $attachments_array;
+    }
+
+    /**
+     * Document versions
+     *
+     * @return array of versions
+     */
+    public function versions():array{
+        // definition
+        $versions_array=array();
+        // check directory
+        if(is_dir($this->DIR."/versions/")){
+            // scan directory for documents
+            $elements=scandir($this->DIR."/versions/");
+            // cycle all elements
+            foreach($elements as $element_fe){
+                // skip directories
+                if(is_dir($this->DIR."/versions/".$element_fe)){continue;}
+                $file_extension=explode(".",$element_fe);
+                // check extensions
+                if(end($file_extension)!=='md'){continue;}
+                // make element
+                $version=new stdClass();
+                $version->label=$element_fe;
+                $version->url=$this->URL."?version=".substr($element_fe,0,-3);
+                // add element to documents array
+                $versions_array[]=$version;
+            }
+        }
+        // sort versions
+        sort($versions_array);
+        // return
+        return $versions_array;
+    }
+
+    /**
+     * Document hierarchy
+     *
+     * @return array of hierarchy links
+     */
+    public function hierarchy():array{
+        // definition
+        $hierarchy_array=array();
+        // explode document path
+        $breadcrumbs=explode("/",$this->ID);
+        // cycle all segments
+        foreach($breadcrumbs as $index=>$breadcrumb){
+            // make path
+            $path=null;
+            foreach($breadcrumbs as $index_link=>$breadcumb_link){if($index_link<=$index){$path.="/".$breadcumb_link;}}
+            // build item
+            $item=new stdClass();
+            $item->label=$breadcrumb;
+            $item->path=substr($path,1);
+            // add item to hierarchy array
+            $hierarchy_array[]=$item;
+        }
+        // return
+        return $hierarchy_array;
+    }
+
+
+
+    /**
+     * Document title
+     *
+     * @param string $document Document ID
+     * @return string Document title
+     */
+    static function getTitle(string $document):string{
+        $title='';
+        // make path
+        $content_path=DIR."datasets/documents/".$document."/content.md";
+        // load content line by line to find document title if exist
+        if(file_exists($content_path)){
+            $handle=fopen($content_path,"r");
+            while(!feof($handle)){
+                $line=fgets($handle);
+                if(substr($line,0,2)=="# "){
+                    $title=trim(substr($line,1));
+                    break;
+                }
+            }
+            fclose($handle);
+        }
+        if(!strlen($title)){
+            // make title by path
+            $hierarchy=explode("/",$document);
+            $title=ucwords(str_replace("-"," ",end($hierarchy)));
+        }
+        // return
+        return $title;
+    }
+
+    /**
+     * Document Update Date
+     *
+     * @param string $document Document ID
+     * @return integer Update Date
+     */
+    static function getUpdateDate(string $document):string{
+        $date=0;
+        // make path
+        $content_path=DIR."datasets/documents/".$document."/content.md";
+        // load content line by line to find document title if exist
+        if(file_exists($content_path)){
+            $date=filemtime($content_path);
+        }
+        // return
+        return $date;
+    }
+
+    /**
+     * Document list in path
+     *
+     * @param ?string $parent Parent Document ID
+     * @return Document[] array of documents
+     */
+    static function list(?string $parent=null):array{
+        $documents_array=array();
+        // check parameters
+        if(substr((string)$parent,-1)!="/"){$parent.="/";}
+        if($parent=="/"){$parent=null;}
+        // make directory full path
+        $directory_path=DIR."datasets/documents/".$parent;
+        // check for directory
+        if(is_dir($directory_path)){
+            // scan directory for documents
+            $elements=scandir($directory_path);
+            // cycle all elements
+            foreach($elements as $element_fe){
+                // skip versioning and files
+                if(in_array($element_fe,array(".","..","versions"))){continue;}
+                if(!is_dir($directory_path.$element_fe)){continue;}
+                // build directory
+                $document=new stdClass();
+                $document->id=$element_fe;
+                $document->path=$parent.$element_fe;
+                $document->url=URL.$document->path;
+                $document->dir=$directory_path.$element_fe;
+                // add element to documents array
+                $documents_array[]=$document;
+            }
+        }
+        // return
+        return $documents_array;
+    }
+
+
+    /**
+     * Documents Index
+     *
+     * @param ?string $parent Parent document ID
+     * @return Document[] array of Documents
+     */
+    static function index(?string $parent=null):array{
+        // definitions
+        $index_array=array();
+        $documents_array=array();
+        // get document list
+        $directories_array=Document::list($parent);
+        // build documents array
+        if(count($directories_array)){
+            // cycle all documents
+            foreach($directories_array as $document_fe){
+                if($document_fe->id=="homepage"){continue;}
+                // definitions
+                $document_url=$parent."/".$document_fe->id;
+                $document_label=Document::getTitle($document_url);
+                // check document url
+                if(substr($document_url,0,1)=="/"){$document_url=substr($document_url,1);}
+                // add document to documents array
+                $documents_array[$document_url]=$document_label;
+            }
+        }
+        // sort document array by title
+        asort($documents_array, SORT_NATURAL);
+        // cycle all documents and build index array
+        foreach($documents_array as $url_fe=>$label_fe){
+            // build index element
+            $element=new stdClass();
+            $element->label=$label_fe;
+            $element->url=$url_fe;
+            // add element to index array
+            $index_array[]=$element;
+        }
+        // return
+        return $index_array;
+    }
+
+    /**
+     * Documents search in path
+     *
+     * @param string $query String for search
+     * @param ?string $parent Parent Document ID
+     * @return array of results
+     */
+    static function search(string $query,?string $parent=null):array{
+        // Decode HTML entities
+        $query = html_entity_decode($query);
+        // trim the query to remove leading and trailing spaces
+        $query = trim($query);
+        // return an empty array if the query is empty after trimming
+        if (empty($query)) {
+            return array();
+        }
+        // parse the query into phrases and individual words
+        preg_match_all('/"([^"]+)"|(\S+)/', $query, $matches);
+        $queries_array = array_filter(array_merge($matches[1], $matches[2]));
+        // tree to array
+        function tree_to_array(&$array,$parent=null){
+            foreach(Document::list($parent) as $dir_fe){
+                $array[]=$dir_fe->path;
+                tree_to_array($array,$dir_fe->path);
+            }
+        }
+        // definitions
+        $paths_array=array();
+        $matches_array=array();
+        // get all documents directories recursively
+        tree_to_array($paths_array,$parent);
+        //wdf_dump($paths_array);
+        // cycle all directories
+        foreach($paths_array as $path_fe){
+            // check if content file exist
+            if(file_exists(DIR."datasets/documents/".$path_fe."/content.md")){
+                // open file handle for read
+                $handle=fopen(DIR."datasets/documents/".$path_fe."/content.md","r");
+                if($handle){
+                    while(!feof($handle)){
+                        // get line in buffer
+                        $buffer=fgets($handle);
+                        // define a buffer id
+                        $buffer_id=md5($buffer.rand());
+                        // cycle all query words
+                        foreach($queries_array as $query_fe){
+                            // check for query word
+                            if(stripos($buffer,$query_fe)!==false){
+                                // escape buffer for security
+                                $buffer=htmlspecialchars($buffer);
+                                // highlight query word in buffer
+                                $buffer=self::highlighting($query_fe,$buffer);
+                                $matches_array[$path_fe][$buffer_id]=$buffer;
+                                // skip current file after 3 matches
+                                if(count($matches_array[$path_fe])>2){continue(3);}
+                            }
+                        }
+                    }
+                    fclose($handle);
+                }
+            }
+        }
+        return $matches_array;
+    }
+
+    private static function highlighting($search,$string){
+        $index=0;
+        $result="";
+        while($index<strlen($string)){
+            if(strtolower(substr($string,$index,strlen($search)))===strtolower($search)){
+                $result.="<mark>".substr($string,$index,strlen($search))."</mark>";
+                $index=$index+strlen($search);
+            }else{
+                $result.=substr($string,$index,1);
+                $index++;
+            }
+        }
+        return $result;
+    }
 
     /**
      * Get the list of last edited documents