.o1 {
border: 2px solid black;
outline-style: solid;
outline-color: #ff0000; /* hex value of red */
}
.o2 {
border: 2px solid black;
outline-style: dotted;
outline-color: hsl(120, 100%, 50%); /* hsl value of green */
}
.o3 {
border: 2px solid black;
outline-style: outset;
outline-color: grey;
}