teachcloud-print-web/card/assets/styles/icons.scss

// icon
.icon {
  display: inline-block;
  vertical-align: middle;
  background-repeat: no-repeat;
  background-size: 100% 100%;

  &-checked {
    width: 20px;
    height: 20px;
    background-image: url(../images/icon-checked.png);
  }
  &-doubt {
    background-image: url(../images/icon-doubt.png);
    width: 50px;
    height: 50px;
  }

  &-help {
    background-image: url(../images/icon-help.png);
    width: 32px;
    height: 32px;
  }
  &-back {
    background-image: url(../images/icon-back.png);
    width: 32px;
    height: 32px;
  }
  &-two-gray {
    background-image: url(../images/icon-two-gray.png);
    width: 12px;
    height: 10px;
  }
  &-two-white {
    background-image: url(../images/icon-two-white.png);
    width: 12px;
    height: 10px;
  }
  &-three-gray {
    background-image: url(../images/icon-three-gray.png);
    width: 16px;
    height: 10px;
  }
  &-three-white {
    background-image: url(../images/icon-three-white.png);
    width: 16px;
    height: 10px;
  }
  &-four-gray {
    background-image: url(../images/icon-four-gray.png);
    width: 18px;
    height: 10px;
  }
  &-four-white {
    background-image: url(../images/icon-four-white.png);
    width: 18px;
    height: 10px;
  }
}