width device-width What is what? Confused

Question

I've read two articles: https://www.quirksmode.org/mobile/viewports.html https://www.quirksmode.org/mobile/viewports2.html

I am really confused why is width size of window in first article and size of screen in second article. What have I missed?

Answer 1

see below image

Device Screen or Device Width is the width of entire desktop or monitor. In my case it is 1679px wide. (marked with yellow highlighter.. I have highlighted Screen height instead of width. Sorry for that.

And width Screen size window with id width of browser window . in my case this is 1100px wide approximate . i have marked this with red pen.

Hope this will help you.