[fix] apply background color to ":after" (#4476)
[fix] apply background color to ":after" (#4476)

* [fix] apply background color to ":after"

* [modify] break long line
shirasagi/shirasagi,ShinjiTanimoto/shirasagi,sunny4381/shirasagi,ShinjiTanimoto/shirasagi,shirasagi/shirasagi,ShinjiTanimoto/shirasagi,sunny4381/shirasagi,sunny4381/shirasagi,ShinjiTanimoto/shirasagi,shirasagi/shirasagi,sunny4381/shirasagi,shirasagi/shirasagi