These styles alter the default document flow.
Use positions with caution.
They are often unnecessary and commonly misused.
See the Guide to Basics for more info.
.relative { position: relative }
.absolute { position: absolute }
.fixed { position: fixed }
.top-0 { top: 0 }
.right-0 { right: 0 }
.bottom-0 { bottom: 0 }
.left-0 { left: 0 }
.z1 { z-index: 1 }
.z2 { z-index: 2 }
.z3 { z-index: 3 }
.z4 { z-index: 4 }
.absolute-center {
top: 0;
right: 0;
bottom: 0;
left: 0;
margin: auto;
display: table;
}