// The only colors used.
$grey: #CCC;
$black: #000;
$white: #FFF;

$base: 10px;

.container {
  width: 100%;
  position: absolute;
  top: 0;
  bottom: 0;
  display: -webkit-flex;
  display: flex;
  align-items: center;
  justify-content: center;
}

.mask {
  width: 50*$base;
  height: 50*$base;
  position: relative;
  overflow: hidden;
}
.content {
  width: 50*sqrt(2)*$base;
  height: 50*sqrt(2)*$base;

  transform: rotate(45deg);
  position: absolute;
  top: -100px;
  left: -100px;
}

.bar {
  width: 100%;
  height: $base;
  margin-top: 5*$base;
  background: $black;
  position: relative;
}

.barb {
  height: 4*$base;
  width: $base;
  background: $black;
  float: left;
  margin: 1*$base;
  margin-top: -1.5*$base;
}

.positive {
  transform: skewX(45deg);
}
.negative {
  transform: skewX(-45deg);
}

.content:hover {
  .barb {
    display: none;
  }  
}

@import url(http://fonts.lug.ustc.edu.cn/css?family=Open+Sans);
.caption {
  background: $white;
  color: $black;
  position: absolute;
  top: 0px;
  left: 0px;
  z-index: 100;
  font-size: 2em;
  text-align: center;
  width: 100%;
  font-family: Open Sans, sans-serif;
}