diff --git a/src/Element/BookCollection.php b/src/Element/BookCollection.php
index 774487e..9a424da 100644
--- a/src/Element/BookCollection.php
+++ b/src/Element/BookCollection.php
@@ -72,7 +72,7 @@ class BookCollection {
 	
 	public function getHtml (): string {
 		$str = "";
-		if ($this->name != self::ROOT) $str .= "<li class='book-collection fold'><a class='book-collection' href='#'>$this->name<i class='exc-trigger fa'></i></a><ul class='book-collection summary'>";
+		if ($this->name != self::ROOT) $str .= "<li class='book-collection fold" . ($this->getBook(PageMeta::$book->getId())==null?"":"on") . "'><a class='book-collection' href='#'>$this->name<i class='exc-trigger fa'></i></a><ul class='book-collection summary'>";
 		foreach ($this->array as $node) {
 			$str .= $node->getHtml();
 		}
diff --git a/src/Element/BookContent/Chapter.php b/src/Element/BookContent/Chapter.php
index 5eed99b..f48e262 100644
--- a/src/Element/BookContent/Chapter.php
+++ b/src/Element/BookContent/Chapter.php
@@ -66,7 +66,7 @@ class Chapter {
 	
 	public function getSummaryHtml (): string {
 		$str = "";
-		if ($this->parent != null) $str .= "<li class='chapter fold'><a class='page-chapter' href='#'>$this->name<i class='exc-trigger fa'></i></a><ul class='page-chapter summary'>";
+		if ($this->parent != null) $str .= "<li class='chapter fold" . ($this->getPage(PageMeta::$page->getId())==null?"":"on") . "'><a class='page-chapter' href='#'>$this->name<i class='exc-trigger fa'></i></a><ul class='page-chapter summary'>";
 		foreach ($this->childs as $node) {
 			$str .= $node->getSummaryHtml();
 		}