CSS / Responsive webdesign - Multiple pages?

Hello!

Im fresh HTML & CSS beginner, and i would like to ask how to use media querries and CSS on diffrent pages on your website. I know there is many ways out there, but i can’t find much info about this, perhaps it has to do with my searching abilities.

I would like to find a way that i can use to make this as simple and sematic as possible. How i currently changed my CSS from page1 to page2 is that on page2 i deleted main_content section, (i let header,banner,nav,footer be the same) and just added class main_page2 on the container holding what is between header and footer on page2, is this a decent way of doing it or do you have any other suggestions?

And when it comes to media querries, im not really sure where to start, i will create a new CSS file for all the MQ inputs.

I hope this made some sense, Its still early so bare with me, cheers :slight_smile: