给Butterfly加上顶部加载条

.pace {
  -webkit-pointer-events: none;
  pointer-events: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  user-select: none;
}

.pace-inactive {
  display: none;
}

.pace .pace-progress {
  background: #e90f92;
  position: fixed;
  z-index: 2000;
  top: 0;
  right: 100%;
  width: 100%;
  height: 2px;
}

.pace .pace-progress-inner {
  display: block;
  position: absolute;
  right: 0px;
  width: 100px;
  height: 100%;
  box-shadow: 0 0 10px #e90f92, 0 0 5px #e90f92;
  opacity: 1.0;
  -webkit-transform: rotate(3deg) translate(0px, -4px);
  -moz-transform: rotate(3deg) translate(0px, -4px);
  -ms-transform: rotate(3deg) translate(0px, -4px);
  -o-transform: rotate(3deg) translate(0px, -4px);
  transform: rotate(3deg) translate(0px, -4px);
}

.pace .pace-activity {
  display: block;
  position: fixed;
  z-index: 2000;
  top: 15px;
  right: 15px;
  width: 14px;
  height: 14px;
  border: solid 2px transparent;
  border-top-color: #e90f92;
  border-left-color: #e90f92;
  border-radius: 10px;
  -webkit-animation: pace-spinner 400ms linear infinite;
  -moz-animation: pace-spinner 400ms linear infinite;
  -ms-animation: pace-spinner 400ms linear infinite;
  -o-animation: pace-spinner 400ms linear infinite;
  animation: pace-spinner 400ms linear infinite;
}

@-webkit-keyframes pace-spinner {
  0% { -webkit-transform: rotate(0deg); transform: rotate(0deg); }
  100% { -webkit-transform: rotate(360deg); transform: rotate(360deg); }
}
@-moz-keyframes pace-spinner {
  0% { -moz-transform: rotate(0deg); transform: rotate(0deg); }
  100% { -moz-transform: rotate(360deg); transform: rotate(360deg); }
}
@-o-keyframes pace-spinner {
  0% { -o-transform: rotate(0deg); transform: rotate(0deg); }
  100% { -o-transform: rotate(360deg); transform: rotate(360deg); }
}
@-ms-keyframes pace-spinner {
  0% { -ms-transform: rotate(0deg); transform: rotate(0deg); }
  100% { -ms-transform: rotate(360deg); transform: rotate(360deg); }
}
@keyframes pace-spinner {
  0% { transform: rotate(0deg); transform: rotate(0deg); }
  100% { transform: rotate(360deg); transform: rotate(360deg); }
}
/* 在下面修改进度条外观 */
.pace .pace-progress {
  background: #1ef4fbec; /*进度条颜色*/
  height: 3px;/* 进度条厚度 */
}
.pace .pace-progress-inner {
  box-shadow: 0 0 10px #1ef4fbce, 0 0 5px #1ecffbd0; /*阴影颜色*/
}
.pace .pace-activity {
  border-top-color: #1edafbe5;  /*上边框颜色*/
  border-left-color: #1ef4fbec;  /*左边框颜色*/
}

<script src="//cdn.bootcss.com/pace/1.0.2/pace.min.js"></script>