User Agent is: Mozilla/5.0 (Linux; Android 8.1.0; A501DL Build/OPM1.171019.011; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/100.0.4896.88 Mobile Safari/537.36
Challenge: Improve Compatibility with Browser Fallbacks
Let’s improve our browser compatibility by adding another background declaration right before the existing declaration and set its value to red .
If we watch your code, you added the background-color property and not the one asked in the challenge. background is a super property that include background-color, so your code is not wrong but as you need to add a fallback for the background property, you should use the same property.
Other issue is your selector, the challenge doesn’t ask to change it.
original one:
.red-box {
}
Yours:
.red-box, red {
}
If you change these things, you should pass the challenge.