Editing Magento (section)

===Presentation Layer===
The graphic and appearance information is called '''(custom) theme'''. A theme is a component of Magento application which provides a consistent look and feel (visual design) for entire application area (for example, storefront or Magento admin) using a combination of custom templates, layouts, styles or images. Out-of-the-box Magento application provides two design themes: '''Luma''', as a demonstration theme, and '''Blank''' as a basis for custom theme creation. Theme Layout files provided by themes:
* Page configuration and generic layout files: 
 <THEME_DIR>/<Namespace>_<Module>/layout
Page layout files: 
 <THEME_DIR>/<Namespace>_<Module>/page_layout

The default or standard layouts are located in:
 <MAGENTO_DIR>/vendor/magento/module-theme/view/frontend/layout/default.xml
 <MOGENTO_DIR>/vendor/magento/module-backend/view/adminhtml/layout/default.xml
 <MOGENTO_DIR>/vendor/magento/theme-frontend-luma/ // Luma theme

The basic components of page design are
* '''layouts''': structure of a web page using an XML file that identifies all the containers and blocks composing the page (1)
* '''containers''': placeholders within that web page structure assigning content structure to a page using container tags within a layout XML file (2)
* '''blocks''': render the [[Magento#UI_Components|UI components]] on a page using block tags within a layout XML file (3)
* '''templates''': blocks use templates to generate the HTML to insert into its parent structural block

[[File:MagentoPageConcepts.PNG]]

There are two options to influence the layout: [https://devdocs.magento.com/guides/v2.2/frontend-dev-guide/layouts/layout-override.html override] or [https://devdocs.magento.com/guides/v2.2/frontend-dev-guide/layouts/layout-extend.html extend]. '''Extending''' layout file is used for modifying of the default one, without replacing, but сhanging and amplifying it with the instructions. If you need to make a lot of changes or if the layout file contains an instruction that we can not change in the file extension, then the only option will be to '''override''' such file. The difference and how-to is described [https://belvg.com/blog/overriding-layout-files-in-magento-2.html here].

====UI Components====
Magento UI components are implemented as a standard module named Magento_UI ([https://devdocs.magento.com/guides/v2.2/ui_comp_guide/bk-ui_comps.html see official doc]).