gtk/tests/reftests/box-shadow-spec-inset.css

GtkButton {
  engine: none;
  border-radius: 0;
  background-image: none;
  border-image: none;
  border-style: none;
  background-color: rgba(0, 0, 0, 0);
  border-width: 0;
}

.row1, .row2, .row3 {
  /*border:5px solid blue;*/
  border-width: 5;
  border-style: solid;
  border-color: blue;
  background-color:orange;
}

.column1 {
  border-radius: 20/*px*/;
}

.column2 {
  border-radius: 0;
}

.row2 {
  box-shadow:
    rgba(0,0,0,1)
    15/*px*/ 15/*px*/
    inset
}

.row3 {
  box-shadow:
    rgba(0,0,0,1)
    15/*px*/ 15/*px*/ 0
    10/*px*/ /*spread*/
    inset
}

.reference-border {
  border-width: 5;
  border-style: solid;
  border-color: blue;
}

.reference-background {
  background-color: orange;
}

.reference-shadow {
  background-color: rgba(0,0,0,1);
}

.reference-padding-radius {
  border-radius: 15
}

.reference-radii1 {
  border-radius: 15 0 10;
}

.reference-radii2 {
  border-radius: 5 0 10;
}