将以下代码添加到CSS

.btn-etable {
  color: #fff;
  background-color: #d92b3a;
  border-color: #d92b3a;
}

.btn-etable:hover,
.btn-etable.selected {
  color: #d92b3a;
  background-color: #fff;
  border-color: #d92b3a;
}

.btn-ppl {
  width: 48px;
  height: 48px;
  margin: 2px;
}

.callendar {
  display: flex;
  align-items: stretch;
  flex-direction: column;
  width: 100%;
}

.week,
.callendar_header {
  display: flex;
  align-items: stretch;
  flex-direction: row;
  justify-content: stretch;
}

.callendar_header {
  order: "-1"
}

.callendar_header span {
  width: 48px;
  margin: 1px;
  text-align: center;
  flex-grow: 1;
}

.callendar-item,
.blank {
  width: 48px;
  flex-grow: 1;
  margin: 1px;
}

将解决！