.flex-wrap{
  display: block;
  width: 100%;
  margin-bottom: 15px;
}

.flex-btn-box{
  display: -ms-flexbox;
  display: flex;
  -ms-flex-wrap: wrap;
  flex-wrap: wrap;
  box-sizing: border-box;
  width: 100%;
  border-radius: 0.25rem;
  overflow: hidden;
}

.flex-btn-box div{
  flex: 0 0 50%;
  max-width: 50%;
  font-size: 1rem;
  padding: 0.375rem 0.75rem;
  cursor: pointer;
  color: #495057;
  background: #ffffff;
  border: none;
  outline: none;
  border: 2px solid #ffffff;
  cursor: pointer;
}

.flex-btn-box div:hover, .flex-btn-box div.active{
  background: #e57426;
  color: #000000;
  border: 2px solid #e57426;
}

.flex-btn-box div.non-active-valid{
  border: 2px solid #e57426;
}

@media screen and (max-width: 540px){
  .flex-btn-box div{
    flex: 0 0 100%;
    max-width: 100%;
  }
  .flex-btn-box div:not(:last-child){
    margin-bottom: 15px;
  }
}