.container {
    max-width: 840px;
  }
  
  .header {
    background-color: #2b2b2b;
    background-image: -webkit-linear-gradient(bottom left, hsla(0, 0%, 0%, .25) 25%, transparent 25%, transparent 75%, hsla(0, 0%, 0%, .25) 75%, hsla(0, 0%, 0%, .25)),
    -webkit-linear-gradient(bottom left, hsla(0, 0%, 0%, .25) 25%, transparent 25%, transparent 75%, hsla(0, 0%, 0%, .25) 75%, hsla(0, 0%, 0%, .25));
    background-image: -o-linear-gradient(bottom left, hsla(0, 0%, 0%, .25) 25%, transparent 25%, transparent 75%, hsla(0, 0%, 0%, .25) 75%, hsla(0, 0%, 0%, .25)),
    -o-linear-gradient(bottom left, hsla(0, 0%, 0%, .25) 25%, transparent 25%, transparent 75%, hsla(0, 0%, 0%, .25) 75%, hsla(0, 0%, 0%, .25));
    background-image: linear-gradient(to top right, hsla(0, 0%, 0%, .25) 25%, transparent 25%, transparent 75%, hsla(0, 0%, 0%, .25) 75%, hsla(0, 0%, 0%, .25)),
    linear-gradient(to top right, hsla(0, 0%, 0%, .25) 25%, transparent 25%, transparent 75%, hsla(0, 0%, 0%, .25) 75%, hsla(0, 0%, 0%, .25));;
    background-position: 0 0, 2px 2px;
    background-size: 4px 4px;
  }
  
  .footer {
    padding: 30px 0;
  }
  
  .image-set {
    font-size: 20px;
    margin-left: -5px;
    margin-right: -5px;
  }
  
  .image-set img {
    display: block;
    width: 193px;
    height: 193px;
  }
  
  .image-set img:hover {
    display: block;
    width: 194px;
    height: 194px;
    /* position: relative; */
    /* top:-20px; */
    /* transition: 0.3s all ease; */
  }

  .image-set a {
    display: inline-block;
    margin-left: 5px;
    margin-right: 5px;
    padding: 2px;
    border: 1px solid #ddd;
    transition: border-color .3s ease;
    cursor: zoom-in;
    margin-bottom:30px;
  }
  
  .image-set a:hover {
    border-color: #aaa;
    border: solid 1px #5f41a5;
    -webkit-transform: scale(1.08);
    transform: scale(1.08);
 
  }
 
  
  /* prettify style */
  
  pre ul,
  pre ol {
    padding: 0;
  }
  
  .com {
    color: #93a1a1;
  }
  
  .lit {
    color: #195f91;
  }
  
  .pun,
  .opn,
  .clo {
    color: #93a1a1;
  }
  
  .fun {
    color: #dc322f;
  }
  
  .str,
  .atv {
    color: #D14;
  }
  
  .kwd,
  .tag {
    color: #1e347b;
  }
  
  .typ,
  .atn,
  .dec,
  .var {
    color: teal;
  }
  
  .pln {
    color: #48484c;
  }
  
  .prettyprint {
    padding: 10px;
    background-color: #f7f7f9;
    border: 1px solid #e1e1e8;
  }