Why not considering leaving spacing for top navigation & bottom taskbar of screen?

Hello my Friends . :wave:

I’m a beginner in figma, and i saw a lot of youtuber that doesn’t take in consideration this issue.

so the problem is when we design a web page with a 1440*1080 frame (for exemple), the designers take all the space of this frame, without taking in consideration the browser top bar height and the window/mac task bar height. so the issue is when you preview the design in the browser (figma preview sucks :smiling_face_with_tear:) all the design get narrowed.

so maybe my question here is not linked to figma directly ? but to general design guidelines ? because all the tutorials that i saw were like “ok the front end will deal with it, it’s not my problem”.

Do we leave space for top and bottom bars or let this issue to “devs” ?