HTML5
Semantic markup; block model; BEM; components reuse; flexbox; forms; centering; positioning; lists, tables; SEO
CSS3
Selectors and their patterns; pseudoelements and pseudoclasses; @media-requests for responsive websites; properties inheritance
Javascript
Adding/removing classes, selecting pattern-matching components; developing basic Javascript elements like expand/scroll buttons, navigation buttons, burger and profile menus
SASS
SCSS tools: variables, @mixin/@include, nesting, conditions, loops
Angular 2+
Using Angular 2+ framework to create complicated single-page applications.
Angular Universal; NgRx; RxJS
React
Using React / Redux to create complicated single-page applications.
React-admin; redux-toolkit; formik
CSS Frameworks
Integrating framework structures and library elements; creating websites fully-based on framework functionality.
Material UI, Bootstrap, UIkit
Linux
Linux management skills gained through constant Linux hosting-migration related tasks