.a404 {
  display: block;
  background-color: #f7f7f7;
  padding-top: 210px;
  padding-bottom: 150px;
}

.a404_img {
  text-align: center;
}

.a404_title {
  margin-top: 30px;
  text-align: center;
  font-family: mon-sb;
  font-size: 50px;
  color: #333;
}

.a404_msg {
  text-align: center;
  font-size: 16px;
  color: #999;
  margin-top: 30px;
  font-family: pop-m;
}

.a404_button {
  font-family: pop-r;
  margin-top: 50px;
  text-align: center;
}

.a404_button a {
  display: inline-block;
  width: 180px;
  height: 40px;
  border: 1px solid #d1d1d1;
  border-radius: 20px;
  color: #666;
  font-size: 14px;
  font-weight: 600;
  line-height: 40px;
  text-align: center;
}

@media only screen and (max-width: 840px) {
  .a404_title {
    font-size: 30px;
  }

  .a404_msg {
    font-size: 14px;
  }

  .a404_button a {
    font-size: 12px;
  }
}