/*コメント*/
/* Font Awesome Icons */
@import url(https://maxcdn.bootstrapcdn.com/font-awesome/4.2.0/css/font-awesome.min.css);

/* Back to top button
=====================================*/
.back-to-top {z-index:20;
  display: none;
  -webkit-transition: all 0.3s ease;
  -moz-transition: all 0.3s ease;
  -o-transition: all 0.3s ease;
  transition: all 0.3s ease;
  background-color: #2B2B2B;
  border-radius: 4px;
  position: fixed;
  opacity: 1;
  right: 20px;
  bottom: 40px;
  padding: 20px;
}
.back-to-top:after {
  content: "\f102";
  font-family: fontawesome;
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  margin: auto;
  font-size: 20px;
  width: 20px;
  height: 20px;
  color: #FFF;
  line-height: 20px;
  text-align: center;
}