Firebug doesn’t take a master’s degree. We talked about it quite a bit and about how it can help you solve problems in your code, such as you are asking about now, very easily. Just give it a quick review and use it a time or two. You know what they say about learning to ride a bicycle…
Content does not fit viewport - #25 by ronpat
Content does not fit viewport - #33 by qim
https://www.sitepoint.com/community/t/content-does-not-fit-viewport/201719/35
https://www.sitepoint.com/community/t/content-does-not-fit-viewport/201719/40 <= Follow the Numbers.