2 Answers
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nope. your browser recognises html as a web page structure, css as it's looking and js as it's behavior. this 3 langs form a base of modern web technology.
what frameworks do? they provide server-side functionality, like dynamic data getting from database, file access, login functions, etc.
how are they doing this? they answer somebody's attempt to download from specified domain address.
for example, you have a website at www.mysite.com. in root folder you have your index.html file. what if you type some address like www.mysite.com/something ?
if you have folder "something" and index.html in it, it will load. if not - you'll get 404.
but if you add this node to server functionality, framework can answer and can give you some info. this info would be a text, no more. it might contain json data, plain text from files, but also html code (with css and js in it, if needed). in this case there would be a page on this address, but fully dynamic and it wouldn't exist in folder physically.
returning to your basic question: without knowing html+css+js you can't build web pages. even frameworks must return html code to act like a page, without tags, styles and functions they will only return some text, and your browser will look like text editor.
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thank you very much @Demeth