How to setup background colors of two Shinyapp in a rmarkdown file?

I inserted two Shinyapps in a rmarkdown file. I called one external .scss file to style one Shinyapp. There are two different .scss files. I set the background color in the scss file as follows:

body {
  background: #f2ffe4; (#007BA7 was the color in the different scss file)
}

However, only the first Shinyapp background changed, the second Shinyapp background remained no change.