.def_lst {
  display: flex;
  flex-wrap: wrap;
}
.def_lst dt, 
.def_lst dd {
    padding: 18px;
}
.def_lst dt {
  	border-bottom: 2px solid;
    text-align: center;
    font-family: 'Koburina Gothic W6 JIS2004', sans-serif;
    font-size: 107%;
    width: 240px;
}
.def_lst dd {
    border-bottom: 1px solid;
    margin-left: 4px;
    width: calc(100% - 244px);
    padding: 19px;
}
@media screen and (max-width: 767px) {
  .def_lst {
    display: block;
  }
  .def_lst dt,
  .def_lst dd {
    width: 100%;
    margin-left: 0;
  }
}