Product landing <i class="fa fa-3x fa-fire"></i>

where are these icons coming from.
i copy and paste the html and css code into text file on desktop and run it but doesn’t look the same.
here is example…why its not looking same?

everything is brooken…seems only few css is working

It’s because you’re using SASS. You need to go to the CSS settings and specify a CSS preprocessor.
Once you do that it works:

<i class=“fa fa-3x fa-fire”></i>

For this type of icon to work you have to add font awesome.