在butterfly_config.yml的bottom处引入如下内容

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

在如下目录新建

/themes/butterfly/source/css

pace-theme-flash.css

.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*/
}

在head处引入如下内容

- <link rel="stylesheet" href="/css/pace-theme-flash.css">

然后就大功告成了。如果要改进度条颜色可以在pace-theme-flash.css里修改。