.area {
  width: 800px;
  margin: auto;
  flex-wrap: wrap;
  display: flex;
  white-space: nowrap;  /*途中の折り返し禁止*/
/*  RepeatColumns:2;*/
}
 
.tab_class {
  width: calc(100%/5);
  height: 50px;
  background-color: darkgrey;
  line-height: 50px;
  font-size: 15px;
  text-align: center;
  display: block;
  float: left;
  order: -1;
}
 
input[name="tab_name"] {
  display: none;
}
 
input:checked + .tab_class {
  background-color: cadetblue;
  color: aliceblue;
}
 
.content_class {
  display: none;
  width: 100%;
}
 
input:checked + .tab_class + .content_class {
  display: block;
}
