diff --git a/system/src/Grav/Framework/ContentBlock/ContentBlock.php b/system/src/Grav/Framework/ContentBlock/ContentBlock.php
new file mode 100644
index 000000000..c446c3a1b
--- /dev/null
+++ b/system/src/Grav/Framework/ContentBlock/ContentBlock.php
@@ -0,0 +1,229 @@
+<?php
+/**
+ * @package    Grav\Framework\ContentBlock
+ *
+ * @copyright  Copyright (C) 2014 - 2017 RocketTheme, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Framework\ContentBlock;
+
+/**
+ * Class to create nested blocks of content.
+ *
+ * $innerBlock = ContentBlock::create();
+ * $innerBlock->setContent('my inner content');
+ * $outerBlock = ContentBlock::create();
+ * $outerBlock->setContent(sprintf('Inside my outer block I have %s.', $innerBlock->getToken()));
+ * $outerBlock->addBlock($innerBlock);
+ * echo $outerBlock;
+ *
+ * @package Grav\Framework\ContentBlock
+ */
+class ContentBlock implements ContentBlockInterface
+{
+    protected $version = 1;
+    protected $id;
+    protected $tokenTemplate = '@@BLOCK-%s@@';
+    protected $content = '';
+    protected $blocks = [];
+
+    /**
+     * @param string $id
+     * @return static
+     */
+    public static function create($id = null)
+    {
+        return new static($id);
+    }
+
+    /**
+     * @param array $serialized
+     * @return ContentBlockInterface
+     */
+    public static function fromArray(array $serialized)
+    {
+        try {
+            $type = isset($serialized['_type']) ? $serialized['_type'] : null;
+            $id = isset($serialized['id']) ? $serialized['id'] : null;
+
+            if (!$type || !$id || !is_a($type, 'Grav\Framework\ContentBlock\ContentBlockInterface', true)) {
+                throw new \RuntimeException('Bad data');
+            }
+
+            /** @var ContentBlockInterface $instance */
+            $instance = new $type($id);
+            $instance->build($serialized);
+        } catch (\Exception $e) {
+            throw new \RuntimeException(sprintf('Cannot unserialize Block: %s', $e->getMessage()), $e->getCode(), $e);
+        }
+
+        return $instance;
+    }
+
+    /**
+     * Block constructor.
+     *
+     * @param string $id
+     */
+    public function __construct($id = null)
+    {
+        $this->id = $id ? (string) $id : $this->generateId();
+    }
+
+    /**
+     * @return string
+     */
+    public function getId()
+    {
+        return $this->id;
+    }
+
+    /**
+     * @return string
+     */
+    public function getToken()
+    {
+        return sprintf($this->tokenTemplate, $this->getId());
+    }
+
+    /**
+     * @return array
+     */
+    public function toArray()
+    {
+        $blocks = [];
+        /**
+         * @var string $id
+         * @var ContentBlockInterface $block
+         */
+        foreach ($this->blocks as $block) {
+            $blocks[$block->getId()] = $block->toArray();
+        }
+
+        $array = [
+            '_type' => get_class($this),
+            '_version' => $this->version,
+            'id' => $this->id,
+        ];
+
+        if ($this->content) {
+            $array['content'] = $this->content;
+        }
+
+        if ($blocks) {
+            $array['blocks'] = $blocks;
+        }
+
+        return $array;
+    }
+
+    /**
+     * @return string
+     */
+    public function toString()
+    {
+        if (!$this->blocks) {
+            return (string) $this->content;
+        }
+
+        $tokens = [];
+        $replacements = [];
+        foreach ($this->blocks as $block) {
+            $tokens[] = $block->getToken();
+            $replacements[] = $block->toString();
+        }
+
+        return str_replace($tokens, $replacements, (string) $this->content);
+    }
+
+    /**
+     * @return string
+     */
+    public function __toString()
+    {
+        try {
+            return $this->toString();
+        } catch (\Exception $e) {
+            return sprintf('Error while rendering block: %s', $e->getMessage());
+        }
+    }
+
+    /**
+     * @param array $serialized
+     */
+    public function build(array $serialized)
+    {
+        $this->checkVersion($serialized);
+
+        $this->id = isset($serialized['id']) ? $serialized['id'] : $this->generateId();
+
+        if (isset($serialized['content'])) {
+            $this->setContent($serialized['content']);
+        }
+
+        $blocks = isset($serialized['blocks']) ? (array) $serialized['blocks'] : [];
+        foreach ($blocks as $block) {
+            $this->addBlock(self::fromArray($block));
+        }
+    }
+
+    /**
+     * @param string $content
+     * @return $this
+     */
+    public function setContent($content)
+    {
+        $this->content = $content;
+
+        return $this;
+    }
+
+    /**
+     * @param ContentBlockInterface $block
+     * @return $this
+     */
+    public function addBlock(ContentBlockInterface $block)
+    {
+        $this->blocks[$block->getId()] = $block;
+
+        return $this;
+    }
+
+    /**
+     * @return string
+     */
+    public function serialize()
+    {
+        return serialize($this->toArray());
+    }
+
+    /**
+     * @param string $serialized
+     */
+    public function unserialize($serialized)
+    {
+        $array = unserialize($serialized);
+        $this->build($array);
+    }
+
+    /**
+     * @return string
+     */
+    protected function generateId()
+    {
+        return uniqid('', true);
+    }
+
+    /**
+     * @param array $serialized
+     * @throws \RuntimeException
+     */
+    protected function checkVersion(array $serialized)
+    {
+        $version = isset($serialized['_version']) ? (string) $serialized['_version'] : 1;
+        if ($version != $this->version) {
+            throw new \RuntimeException(sprintf('Unsupported version %s', $version));
+        }
+    }
+}
\ No newline at end of file
diff --git a/system/src/Grav/Framework/ContentBlock/ContentBlockInterface.php b/system/src/Grav/Framework/ContentBlock/ContentBlockInterface.php
new file mode 100644
index 000000000..9412ef82f
--- /dev/null
+++ b/system/src/Grav/Framework/ContentBlock/ContentBlockInterface.php
@@ -0,0 +1,75 @@
+<?php
+/**
+ * @package    Grav\Framework\ContentBlock
+ *
+ * @copyright  Copyright (C) 2014 - 2017 RocketTheme, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Framework\ContentBlock;
+
+/**
+ * ContentBlock Interface
+ * @package Grav\Framework\ContentBlock
+ */
+interface ContentBlockInterface extends \Serializable
+{
+    /**
+     * @param string $id
+     * @return static
+     */
+    public static function create($id = null);
+
+    /**
+     * @param array $serialized
+     * @return ContentBlockInterface
+     */
+    public static function fromArray(array $serialized);
+
+    /**
+     * @param string $id
+     */
+    public function __construct($id = null);
+
+    /**
+     * @return string
+     */
+    public function getId();
+
+    /**
+     * @return string
+     */
+    public function getToken();
+
+    /**
+     * @return array
+     */
+    public function toArray();
+
+    /**
+     * @return string
+     */
+    public function toString();
+
+    /**
+     * @return string
+     */
+    public function __toString();
+
+    /**
+     * @param array $serialized
+     */
+    public function build(array $serialized);
+
+    /**
+     * @param string $content
+     * @return $this
+     */
+    public function setContent($content);
+
+    /**
+     * @param ContentBlockInterface $block
+     * @return $this
+     */
+    public function addBlock(ContentBlockInterface $block);
+}
\ No newline at end of file
diff --git a/system/src/Grav/Framework/ContentBlock/HtmlBlock.php b/system/src/Grav/Framework/ContentBlock/HtmlBlock.php
new file mode 100644
index 000000000..c2537da86
--- /dev/null
+++ b/system/src/Grav/Framework/ContentBlock/HtmlBlock.php
@@ -0,0 +1,374 @@
+<?php
+/**
+ * @package    Grav\Framework\ContentBlock
+ *
+ * @copyright  Copyright (C) 2014 - 2017 RocketTheme, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Framework\ContentBlock;
+
+/**
+ * HtmlBlock
+ *
+ * @package Grav\Framework\ContentBlock
+ */
+class HtmlBlock extends ContentBlock implements HtmlBlockInterface
+{
+    protected $version = 1;
+    protected $frameworks = [];
+    protected $styles = [];
+    protected $scripts = [];
+    protected $html = [];
+
+    /**
+     * @return array
+     */
+    public function getAssets()
+    {
+        $assets = $this->getAssetsFast();
+
+        $this->sortAssets($assets['styles']);
+        $this->sortAssets($assets['scripts']);
+        $this->sortAssets($assets['html']);
+
+        return $assets;
+    }
+
+    /**
+     * @return array
+     */
+    public function getFrameworks()
+    {
+        $assets = $this->getAssetsFast();
+
+        return array_keys($assets['frameworks']);
+    }
+
+    /**
+     * @param string $location
+     * @return array
+     */
+    public function getStyles($location = 'head')
+    {
+        return $this->getAssetsInLocation('styles', $location);
+    }
+
+    /**
+     * @param string $location
+     * @return array
+     */
+    public function getScripts($location = 'head')
+    {
+        return $this->getAssetsInLocation('scripts', $location);
+    }
+
+    /**
+     * @param string $location
+     * @return array
+     */
+    public function getHtml($location = 'bottom')
+    {
+        return $this->getAssetsInLocation('html', $location);
+    }
+
+    /**
+     * @return array
+     */
+    public function toArray()
+    {
+        $array = parent::toArray();
+
+        if ($this->frameworks) {
+            $array['frameworks'] = $this->frameworks;
+        }
+        if ($this->styles) {
+            $array['styles'] = $this->styles;
+        }
+        if ($this->scripts) {
+            $array['scripts'] = $this->scripts;
+        }
+        if ($this->html) {
+            $array['html'] = $this->html;
+        }
+
+        return $array;
+    }
+
+    /**
+     * @param array $serialized
+     */
+    public function build(array $serialized)
+    {
+        parent::build($serialized);
+
+        $this->frameworks = isset($serialized['frameworks']) ? (array) $serialized['frameworks'] : [];
+        $this->styles = isset($serialized['styles']) ? (array) $serialized['styles'] : [];
+        $this->scripts = isset($serialized['scripts']) ? (array) $serialized['scripts'] : [];
+        $this->html = isset($serialized['html']) ? (array) $serialized['html'] : [];
+    }
+
+    /**
+     * @param string $framework
+     * @return $this
+     */
+    public function addFramework($framework)
+    {
+        $this->frameworks[$framework] = 1;
+
+        return $this;
+    }
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     *
+     * @example $block->addStyle('assets/js/my.js');
+     * @example $block->addStyle(['href' => 'assets/js/my.js', 'media' => 'screen']);
+     */
+    public function addStyle($element, $priority = 0, $location = 'head')
+    {
+        if (!is_array($element)) {
+            $element = ['href' => (string) $element];
+        }
+        if (empty($element['href'])) {
+            return false;
+        }
+        if (!isset($this->styles[$location])) {
+            $this->styles[$location] = [];
+        }
+
+        $id = !empty($element['id']) ? ['id' => (string) $element['id']] : [];
+        $href = $element['href'];
+        $type = !empty($element['type']) ? (string) $element['type'] : 'text/css';
+        $media = !empty($element['media']) ? (string) $element['media'] : null;
+        unset($element['tag'], $element['id'], $element['rel'], $element['content'], $element['href'], $element['type'], $element['media']);
+
+        $this->styles[$location][md5($href) . sha1($href)] = [
+                ':type' => 'file',
+                ':priority' => (int) $priority,
+                'href' => $href,
+                'type' => $type,
+                'media' => $media,
+                'element' => $element
+            ] + $id;
+
+        return true;
+    }
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addInlineStyle($element, $priority = 0, $location = 'head')
+    {
+        if (!is_array($element)) {
+            $element = ['content' => (string) $element];
+        }
+        if (empty($element['content'])) {
+            return false;
+        }
+        if (!isset($this->styles[$location])) {
+            $this->styles[$location] = [];
+        }
+
+        $content = (string) $element['content'];
+        $type = !empty($element['type']) ? (string) $element['type'] : 'text/css';
+
+        $this->styles[$location][md5($content) . sha1($content)] = [
+            ':type' => 'inline',
+            ':priority' => (int) $priority,
+            'content' => $content,
+            'type' => $type
+        ];
+
+        return true;
+    }
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addScript($element, $priority = 0, $location = 'head')
+    {
+        if (!is_array($element)) {
+            $element = ['src' => (string) $element];
+        }
+        if (empty($element['src'])) {
+            return false;
+        }
+        if (!isset($this->scripts[$location])) {
+            $this->scripts[$location] = [];
+        }
+
+        $src = $element['src'];
+        $type = !empty($element['type']) ? (string) $element['type'] : 'text/javascript';
+        $defer = isset($element['defer']) ? true : false;
+        $async = isset($element['async']) ? true : false;
+        $handle = !empty($element['handle']) ? (string) $element['handle'] : '';
+
+        $this->scripts[$location][md5($src) . sha1($src)] = [
+            ':type' => 'file',
+            ':priority' => (int) $priority,
+            'src' => $src,
+            'type' => $type,
+            'defer' => $defer,
+            'async' => $async,
+            'handle' => $handle
+        ];
+
+        return true;
+    }
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addInlineScript($element, $priority = 0, $location = 'head')
+    {
+        if (!is_array($element)) {
+            $element = ['content' => (string) $element];
+        }
+        if (empty($element['content'])) {
+            return false;
+        }
+        if (!isset($this->scripts[$location])) {
+            $this->scripts[$location] = [];
+        }
+
+        $content = (string) $element['content'];
+        $type = !empty($element['type']) ? (string) $element['type'] : 'text/javascript';
+
+        $this->scripts[$location][md5($content) . sha1($content)] = [
+            ':type' => 'inline',
+            ':priority' => (int) $priority,
+            'content' => $content,
+            'type' => $type
+        ];
+
+        return true;
+    }
+
+    /**
+     * @param string $html
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addHtml($html, $priority = 0, $location = 'bottom')
+    {
+        if (empty($html) || !is_string($html)) {
+            return false;
+        }
+        if (!isset($this->html[$location])) {
+            $this->html[$location] = [];
+        }
+
+        $this->html[$location][md5($html) . sha1($html)] = [
+            ':priority' => (int) $priority,
+            'html' => $html
+        ];
+
+        return true;
+    }
+
+    /**
+     * @return array
+     */
+    protected function getAssetsFast()
+    {
+        $assets = [
+            'frameworks' => $this->frameworks,
+            'styles' => $this->styles,
+            'scripts' => $this->scripts,
+            'html' => $this->html
+        ];
+
+        foreach ($this->blocks as $block) {
+            if ($block instanceof HtmlBlock) {
+                $blockAssets = $block->getAssetsFast();
+                $assets['frameworks'] += $blockAssets['frameworks'];
+
+                foreach ($blockAssets['styles'] as $location => $styles) {
+                    if (!isset($assets['styles'][$location])) {
+                        $assets['styles'][$location] = $styles;
+                    } elseif ($styles) {
+                        $assets['styles'][$location] += $styles;
+                    }
+                }
+
+                foreach ($blockAssets['scripts'] as $location => $scripts) {
+                    if (!isset($assets['scripts'][$location])) {
+                        $assets['scripts'][$location] = $scripts;
+                    } elseif ($scripts) {
+                        $assets['scripts'][$location] += $scripts;
+                    }
+                }
+
+                foreach ($blockAssets['html'] as $location => $htmls) {
+                    if (!isset($assets['html'][$location])) {
+                        $assets['html'][$location] = $htmls;
+                    } elseif ($htmls) {
+                        $assets['html'][$location] += $htmls;
+                    }
+                }
+            }
+        }
+
+        return $assets;
+    }
+
+    /**
+     * @param string $type
+     * @param string $location
+     * @return array
+     */
+    protected function getAssetsInLocation($type, $location)
+    {
+        $assets = $this->getAssetsFast();
+
+        if (empty($assets[$type][$location])) {
+            return [];
+        }
+
+        $styles = $assets[$type][$location];
+        $this->sortAssetsInLocation($styles);
+
+        return $styles;
+    }
+
+    /**
+     * @param array $items
+     */
+    protected function sortAssetsInLocation(array &$items)
+    {
+        $count = 0;
+        foreach ($items as &$item) {
+            $item[':order'] = ++$count;
+        }
+        uasort(
+            $items,
+            function ($a, $b) {
+                return ($a[':priority'] == $b[':priority']) ? $a[':order'] - $b[':order'] : $a[':priority'] - $b[':priority'];
+            }
+        );
+    }
+
+    /**
+     * @param array $array
+     */
+    protected function sortAssets(array &$array)
+    {
+        foreach ($array as $location => &$items) {
+            $this->sortAssetsInLocation($items);
+        }
+    }
+}
\ No newline at end of file
diff --git a/system/src/Grav/Framework/ContentBlock/HtmlBlockInterface.php b/system/src/Grav/Framework/ContentBlock/HtmlBlockInterface.php
new file mode 100644
index 000000000..08e4caad3
--- /dev/null
+++ b/system/src/Grav/Framework/ContentBlock/HtmlBlockInterface.php
@@ -0,0 +1,94 @@
+<?php
+/**
+ * @package    Grav\Framework\ContentBlock
+ *
+ * @copyright  Copyright (C) 2014 - 2017 RocketTheme, LLC. All rights reserved.
+ * @license    MIT License; see LICENSE file for details.
+ */
+
+namespace Grav\Framework\ContentBlock;
+
+/**
+ * Interface HtmlBlockInterface
+ * @package Grav\Framework\ContentBlock
+ */
+interface HtmlBlockInterface extends ContentBlockInterface
+{
+    /**
+     * @return array
+     */
+    public function getAssets();
+
+    /**
+     * @return array
+     */
+    public function getFrameworks();
+
+    /**
+     * @param string $location
+     * @return array
+     */
+    public function getStyles($location = 'head');
+
+    /**
+     * @param string $location
+     * @return array
+     */
+    public function getScripts($location = 'head');
+
+    /**
+     * @param string $location
+     * @return array
+     */
+    public function getHtml($location = 'bottom');
+
+    /**
+     * @param string $framework
+     * @return $this
+     */
+    public function addFramework($framework);
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     *
+     * @example $block->addStyle('assets/js/my.js');
+     * @example $block->addStyle(['href' => 'assets/js/my.js', 'media' => 'screen']);
+     */
+    public function addStyle($element, $priority = 0, $location = 'head');
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addInlineStyle($element, $priority = 0, $location = 'head');
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addScript($element, $priority = 0, $location = 'head');
+
+
+    /**
+     * @param string|array $element
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addInlineScript($element, $priority = 0, $location = 'head');
+
+    /**
+     * @param string $html
+     * @param int $priority
+     * @param string $location
+     * @return bool
+     */
+    public function addHtml($html, $priority = 0, $location = 'bottom');
+}