html {
    font-family: Arial, Helvetica, sans-serif;
    font-size: 14pt;
    line-height: 1.3;
  }
  
  body {
    width: 800px;
    max-width: 90%;
    margin: 5rem auto;
  }
  
  article {
    margin: 5rem 0;
  }
  
  section {
    margin: 3rem 0;
  }
  
  h1, h2, h3, h4, h5, h6 {
    font-weight: normal;
  }
  
  article > h1 {
    font-weight: bold;
  }
  
  samp {
    display: block;
    margin: 1em 0;
  }
  
  code, kbd {
    color: steelblue;
    font-style: normal;
    font-weight: normal;
  }
  
  code.tag::before {
    content: "<";
  }
  
  code.tag::after {
    content: ">";
  }
  
  ol.instructions {
    background-color: #f2f2f2;
    padding: 1rem 1rem 1rem 2rem;
    color: #666666;
    font-style: italic;
    font-size: 0.8rem;
    line-height: 1.2;
  }
  
  ol.instructions > li {
    margin: 0.4rem 0;
  }
  
  ol.instructions > li:first-child { margin-top: 0; }
  ol.instructions > li:last-child { margin-bottom: 0; }
  
  aside {
    padding: 1rem 2rem;
    color: white;
    background-color: gray;
    font-size: 0.8rem;
    margin: 1em 0;
  }
  
  .overflow-example {
    padding: 1rem;
    border: 1px solid gray;
  }
  
  .portrait {
    width: 125px;
  }
  
  .positioned-element {
    width: 50px;
    height: 50px;
    background-color: #ccc;
  }
  
  .static-example,
  .relative-example,
  .absolute-example,
  .fixed-example,
  .sticky-example {
    border: 1px solid #999;
    padding: 0 1rem;
  }

.grid img{
    width: 150px;
}

.grid{
  padding: 0;
}


.grid li{
  display: block;
    width: 25%;
    text-align: center;
    font-size: 0.8rem;
    margin-bottom: 1rem;
}

.using-inline-block li {
    display: inline-block;
}

.using-inline-block {
    font-size: 0;
}

.using-flex {
  display: flex; 
  flex-wrap: wrap;
}

.using-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr;
}

.using-grid li {
  width: 100%;
}