Typical issue I'm having making a 'Chrome-extension'

#discuss #help

Today I decided to make a Chrome-extension and the typical issue I was having are:

First-The Size

I first created the manifest.json as it described in the Chrome Dev Docs, and then created a file Popup.html and some css and js file also I worked on the extension as a usual website on my browser to avoid again and again reloading the extension but when I loaded it using chrome dev tools the size of every element in the extension block was shrinked .
So tell me why this happening

Second - External Libraries

As I said earlier I was firstly using my browser to do all the stuffs, so I used the font-awesome library but it isn't working in the extension. I Searched about this on Google and found that it's something related to content_security_policy and I have to mention the site in manifest.json.
So, what is content_security_policy and would I have to mention it for each and every external scripts.

Third - How to Search ?

This Problem is the only one which made me write this post.
I mean, How do I search on Google for problem related to Chrome Extension whatever I search it shows me results from chrome webstore for different extension after that it shows blogs suggesting different types of related extension.
No matter what I search it shows me extensions only.