Themes in Magento 2 are set up a bit differently than Magento 1. Some of these changes are as follows:
Less (default) implementation with an internal Less preprocessor
Extended layout methods to move and change blocks
Magento UI library for default components, such as forms, buttons, and more
Installable through Composer
Fallback to module layout, templates, and other public files
Static file generation to improve page load times
In this sample theme, the files are located in app/design/frontend/<Vendor>/<Theme>
. When a theme is installed through Composer, it will be installed in the vendor directory.
In order to work with themes, you should have a basic knowledge of XML, HTML, CSS, and Less as these are used to build your theme.