If you would like to use only style sheet it's probably not possible.
Similar solution is to change border-style to double, e.g.
background-color: rgb(97, 97, 97);
border-style: double;
border-width: 3px;
border-color: rgb(0, 0, 0);
border-radius: 4px;
color:rgb(255, 255, 255);
All available borders.
Relating to padding it's not possible to set a color for it. Explain how it look is here.