Rails 7: Font-awesome icons not showing - ruby-on-rails

Question

I have a problem. In my Rails 7 application I am trying to use Font-Awesome icons. I have installed this npm package and then added:
import "#fortawesome/fontawesome-free"
to my app.ts. After that I checked the page where I have put this icon:
<i class="fa-solid fa-caret-down"></i>
But the icon is not showing up. Going into inspector mode, I can see that the icon has a height and width of 0:0, so something must be wrong with installation, maybe I am missing something. I already tried installing the Font-Awesome gem, instead of the NPM, but that gave me all kinds of errors with ESBuild about not be able to compile .svg files and a few other extensions. What am I missing here with the installation?
UPDATE
After installing the gem font-awesome-sass and running bundle install, I added the import statement like this in my app.scss:
#import "bootstrap/scss/bootstrap";
#import "font-awesome";
Unfortunately this results in the following error output:
✘ [ERROR] [plugin sass-plugin] Can't find stylesheet to import.
╷
9 │ #import "font-awesome";
│ ^^^^^^^^^^^^^^
╵
- 9:9 root stylesheet
/app/node_modules/esbuild/lib/main.js:1596
let error = new Error(`${text}${summary}`);
^
Error: Build failed with 1 error:
error: Can't find stylesheet to import.
╷
9 │ #import "font-awesome";
│ ^^^^^^^^^^^^^^
╵
- 9:9 root stylesheet
at failureErrorWithLog (/app/node_modules/esbuild/lib/main.js:1596:15)
at /app/node_modules/esbuild/lib/main.js:1052:28
at runOnEndCallbacks (/app/node_modules/esbuild/lib/main.js:1468:61)
at buildResponseToResult (/app/node_modules/esbuild/lib/main.js:1050:7)
at /app/node_modules/esbuild/lib/main.js:1162:14
at responseCallbacks.<computed> (/app/node_modules/esbuild/lib/main.js:697:9)
at handleIncomingPacket (/app/node_modules/esbuild/lib/main.js:752:9)
at Socket.readFromStdout (/app/node_modules/esbuild/lib/main.js:673:7)
at Socket.emit (node:events:513:28)
at addChunk (node:internal/streams/readable:324:12) {
errors: [
{
detail: undefined,
id: '',
location: null,
notes: [],
pluginName: 'sass-plugin',
text: "Can't find stylesheet to import.\n" +
'\x1B[34m ╷\x1B[0m\n' +
'\x1B[34m9 │\x1B[0m #import \x1B[31m"font-awesome"\x1B[0m;\n' +
'\x1B[34m │\x1B[0m \x1B[31m ^^^^^^^^^^^^^^\x1B[0m\n' +
'\x1B[34m ╵\x1B[0m\n' +
' - 9:9 root stylesheet'
}
],
warnings: []
}

Answer 1

I see! How strange :)
This is how I have it:
gem "font-awesome-sass", "~> 6.1"
bundle install
#import "bootstrap/scss/bootstrap";
#import "font-awesome";
and icons (FontAwesome 5.15.4 and Free icons that have fas fa-something) work perfectly this way:
<i class="fas fa-search"></i>
but they don't work if I want to use unicode icons as content in ::before and and ::after pseudo selectors. After testing on font awesome's own code on codepen and seeing that unicode icons didn't work if the stack was font awesome free, I gave up and am using bootstrap icons for these purposes.