#content_404 {
  text-align: center;
  margin: 100px 0 40px;
}
.error_title {
  width: 535px;
  margin: 0 auto;
  text-align: center;
  font-size: 28px;
  font-weight: bold;
  margin-bottom: 50px;
  position: relative;
  line-height: 1.3;
  padding-left: 30px;　
}
.error_title:before {
  content: '';
  background: url(../img/logo.png) left center no-repeat;
  left: -86px;
  top: 50%;
  -webkit-transform: translateY(-50%);
  -ms-transform: translateY(-50%);
  -o-transform: translateY(-50%);
  transform: translateY(-50%);
  position: absolute;
  width: 86px;
  height: 75px;
}
.des {
  font-size: 167%;
  padding-left: 20px;
}

.btn_top {
  margin-top: 50px;
}
.btn_top a {
  display: inline-block;
}