.tb-grid {
  width: 100%;
  margin: auto;

  .box,
  .box2,
  .box3 {
    display: inline-block;
  }

  .box {
    width:33.3333%;
    padding-top: 33.3333%;
  }

  .box2 {
    width:66.6666%;
    padding-top: 33.3333%;
  }

  .box3 {
    width:66.6666%;
    padding-top: 66.6666%;
  }

  .box-nano {
    position: relative;
    width: 50%;
    margin: 0;
    padding-top: 50%;
    float: left;
  }

  .item > .item-inner,
  .box-nano > .item-inner {
    position: absolute;
    margin: 0;
    top: 5px;
    right: 5px;
    bottom: 5px;
    left: 5px;
    background-size: cover;
    background-position: 50% 0;
    background-repeat: no-repeat;
    cursor: crosshair;

  }

  .items > .item-inner {
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
  }
}