.rtop,.rbottom{display:block; /*border: 1px dashed pink;*/}

.rtop *,.rbottom *{display:block; height: 1px;overflow: hidden}

.r1{margin: 0 5px;/* border: 1px dashed green;*/}
.r2{margin: 0 3px;/* border: 1px dashed red;*/}
.r3{margin: 0 2px;/*border: 1px dashed purple;*/}
.r4{margin: 0 1px; height: 2px; /*border: 1px dashed orange;*/}

.rs1{margin: 0 2px}
.rs2{margin: 0 1px}