#gallery .block_box.high_box {
  max-height:300px;
  overflow:hidden;
  position:relative;
  transition:.3s;
}
#gallery .block_box.high_box::after{
    display: block;
    position: absolute;
    left: 0;
    bottom: 0;
    width: 100%;
    height: 60px;
    background: linear-gradient(180deg, hsla(0, 0%, 100%, 0) 0, hsla(0, 0%, 100%, .9) 50%, hsla(0, 0%, 100%, .9) 0, #fff);
    content: '';
}

#gallery .read-more{
    position: absolute;
    bottom: 0;
    left: 50%;
    color: #000;
    z-index: 999;
    background: #EED;
    padding: 10px 50px;
    transform: translate(-50%, 0);
}
#gallery .high_box.click_box{
      max-height: 100%;
      transition: .3s:
      padding-bottom: 80px;      
}