Z-index
Use BCL z-index attributes with positioned elements.
BCL mapping
Use z-index with positioned elements. Bootstrap's default utility scale maps to values such as Z0, Z1, Z2, and Z3.
Z1
Z3
<bs-span position="Absolute" z-index="Z1">Z1</bs-span>
<bs-span position="Absolute" z-index="Z3">Z3</bs-span>