#tool-area {
  position: relative;
  padding: 0 8px;
  height: 730px;
  box-sizing: border-box;
  -moz-box-sizing: border-box;
  -webkit-box-sizing: border-box;
}
#ui-area {
  height: 40px;
  width: 100%;
  text-align: center;
}
#ui-area #year {
  display: inline-block;
  width: 100px;
  font-size: 1.2rem;
  font-weight: bold;
  line-height: 40px;
}
#ui-area .btn {
  width: 100px;
  font-size: 1rem;
  font-weight: bold;
  line-height: 40px;
  padding: 0 16px;
}
#ui-area .btn:hover {
  cursor: pointer;
  color: red;
}
#prev {
  float: left;
}
#next {
  float: right;
  text-align: right;
}
.week {
  position: absolute;
  top: 40px;
  display: grid;
  grid-template-columns: repeat(7, 1fr);
  height: 40px;
  width: 584px;
  line-height: 40px;
  text-align: center;
  font-weight: bold;
  border-left: solid 1px gray;
  border-top: solid 1px gray;
}
#week2 {
  top: 680px;
  border-bottom: solid 1px gray;
}
.week .day {
  border-right: solid 1px gray;
}
.week .sunday {
  background-color: pink;
}
.week .saturday {
  background-color: green;
}
#date-list {
  position: relative;
  margin: 40px 0 16px 0;
  width: 100%;
  display: grid;
  grid-template-columns: repeat(7, 1fr);  
  height: 600px;
  overflow-y:scroll;
  -ms-overflow-style: none;
  border-top: solid 1px gray;
  border-left: solid 1px gray;
}
#date-list::-webkit-scrollbar,
#date-list::-webkit-scrollbar {
  display: none;
}
#date-list .date-box {
  padding: 8px;
  text-align: center;
  height: 96px;
  border-right: solid 1px gray;
  border-bottom: solid 1px gray;
}
#date-list .date-box .date {
  font-size: 1.4rem;
  font-weight: bold;
}
#date-list .date-box .holiday-name {
  font-size: 0.6rem;
}
.month {
  position: absolute;
  font-size: 8rem;
  font-weight: bold;
  opacity: 0.1;
  transform: translate(-50%, -50%);
  width: 400px;
  text-align: center;
}
#today {
  border: solid 4px red;

}
#date-list .saturday {
  color: green;
}
#date-list .sunday,
#date-list .holiday {
  color: red;
}