Select options are transparent on Mozilla Firefox - css

Question

I use a lang switcher with land flag as select background that change when the lang change.
Everything works as expected but on Mozilla Firefox the options are transparent, except on hover. I cannot find anything to fix it.
I've made a stackblitz so You can better see the problem: (The images are not the good ones, that why it render "ugly")
https://stackblitz.com/edit/angular-u5jgzt
Thanks for help me / sharing me link that can help me.
app.component.ts
import { Component } from '#angular/core';
#Component({
selector: 'my-app',
templateUrl: './app.component.html',
styleUrls: [ './app.component.css' ]
})
export class AppComponent {
/**
* define the current language in the app
*
* #type {('français' | 'english')}
* #memberof LangSwitcherComponent
*/
currentLang: 'français' | 'english' = 'français';
/**
* Change the translation language
*
* #param {*} event
* #memberof LangSwitcherComponent
* #returns {void}
*/
changeLang(): void {
this.currentLang = this.currentLang === 'français' ? 'english' : 'français';
}
}
app.component.css
select {
-webkit-appearance: none;
-moz-appearance: none;
height: 21px;
width: 21px;
border-radius: 100%;
background: url('https://upload.wikimedia.org/wikipedia/commons/thumb/3/3a/Flag_of_France_%281794%E2%80%931815%2C_1830%E2%80%931958%29.svg/250px-Flag_of_France_%281794%E2%80%931815%2C_1830%E2%80%931958%29.svg.png');
background-size: cover;
border: 1px solid #fff;
color: transparent;
cursor: pointer;
}
select.en {
background: url('https://upload.wikimedia.org/wikipedia/commons/f/f2/Flag_of_Great_Britain_%281707%E2%80%931800%29.svg');
background-size: cover;
}
select option {
background-color: white;
padding: 10px;
}
p {
font-size: 15px;
line-height: 19px;
margin: auto;
margin-top: 1px;
}

Answer 1

You need too specify color CSS in the options
select option {
color: black;
}

Answer 2

Just update the select option style to:
select option {
background-color: white;
padding: 10px;
color: #000;
}
You are setting color: transparent in the select{ } style and that one cascades down to the option.