Sunnyside agency Landing page - HTML, SCSS, JS

This is my first challenge, so i have a couple of questions

• In the style guide file there are defined desktop and mobile resolutions. In that case, does the desktop version of the page has to look good up until that specified mobile resolution or it's just up to me when i switch to mobile or i can also make up my own "tablet" version of the site? Because i think my solution switches to mobile too early.

• When using SCSS for example, is it advisable to use media queries in each class / selector if the breakpoints are mostly if not all the same?

Thank you!