There are already those decorators that you can use: 

• decoration-success: light green
• decoration-primary: light purple
• decoration-info: light blue
• decoration-muted: light gray
• decoration-warning: light brown
• decoration-danger: light red
• decoration-bf: Bold text
• decoration-it:  Italic text

If you want to change the color of the standard decorator, you can add a scss file in static/src/scss, and don't forget to add it in the assets of your manifest.

.o_data_row.decoration-success {
    background-color: #ffcccc !important;
}

I hope this helps!