body {
    font-family: Verdana, sans-serif;
    margin: 0;
  }
  
  * {
    box-sizing: border-box;
  }
  
  *{
    margin: 0;
    padding: 0;
  
  }
  html, body{
    height: 100%;
    font-family: sans-serif;
  }
  
  .header_top{
    background: #00795f;
    padding: 20px 0;
    text-align: center;
    color: white;
  }
  
  .container{
    margin: 0 auto;
  }
  
  .header_bottom{
    background: #2196F3;
    padding: 5px 0;
  }
  
  
  main{
    height: 100vh;
  }
  
  .clearfix:after{
    display: block;
    content: " ";
    clear: both;
  }
  
  .w3-border {
    display: block;
    margin-left: auto;
    margin-right: auto;
    margin-top: 10px;
    padding: 5px;
    width: 50%;
    }
  
  nav ul {
    background-color:#2196F3;
    display:flex;
    flex-direction:column;
    }
    nav ul li{
    list-style-type: none;
    }
    nav ul li a{
    padding:.8rem 1rem;
    display:block;
    text-decoration: none;
    color: black;
    }
    nav ul li:hover{
    background:rgba(0,0,0, .25);
    }
    
    .arrow{
    font-family:FontAwesome;
    float:right;
    }
    .arrow-down::after{
    content:"\f107";
    }
    .arrow-right::after{
    content:"\f105";
    }
    
    
    @media only screen and (max-width:1024px) {
    .has-children ul li a{
      padding-left:2rem;
    }
    
    .has-children ul .has-children ul a{
      padding-left:3rem;
    }
    .arrow-down::after{
      content:"\f107";
    }
    }
    
    @media only screen and (min-width:1024px) {
  
    nav ul{
      flex-direction:row;
    /*     justify-content:flex-end; */
    }
    nav ul li{
      position:relative;
      flex:1 0 auto;
      text-align:left;
    }
    .has-children ul, .has-children ul .has-children ul, .has-children ul .has-children ul .has-children ul{
      display:none;
      width:100%;
      position:absolute;
    }
    .has-children ul .has-children ul{
      left:100%;
      top:0;
    }
    nav ul li:hover ul,  .has-children ul .has-children:hover ul, .has-children ul .has-children ul .has-children:hover ul{
       display:flex;
      flex-direction:column;
    }
    
    }
  
  
    .row > .column {
      padding: 0 8px;
    }
    
    .row:after {
      content: "";
      display: table;
      clear: both;
    }
    
    .column {
      float: left;
      width: 25%;
    }
    
    /* The Modal (background) */
    .modal {
      display: none;
      position: fixed;
      z-index: 1;
      padding-top: 100px;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
      overflow: auto;
      background-color: black;
    }
    
    /* Modal Content */
    .modal-content {
      position: relative;
      background-color: #fefefe;
      margin: auto;
      padding: 0;
      width: 90%;
      max-width: 1200px;
    }
    
    /* The Close Button */
    .close {
      color: white;
      position: absolute;
      top: 10px;
      right: 25px;
      font-size: 35px;
      font-weight: bold;
    }
    
    .close:hover,
    .close:focus {
      color: #999;
      text-decoration: none;
      cursor: pointer;
    }
    
    .mySlides {
      display: none;
    }
    
    .cursor {
      cursor: pointer
    }
    
    /* Next & previous buttons */
    .prev,
    .next {
      cursor: pointer;
      position: absolute;
      top: 50%;
      width: auto;
      padding: 16px;
      margin-top: -50px;
      color: white;
      font-weight: bold;
      font-size: 20px;
      transition: 0.6s ease;
      border-radius: 0 3px 3px 0;
      user-select: none;
      -webkit-user-select: none;
    }
    
    /* Position the "next button" to the right */
    .next {
      right: 0;
      border-radius: 3px 0 0 3px;
    }
    
    /* On hover, add a black background color with a little bit see-through */
    .prev:hover,
    .next:hover {
      background-color: rgba(0, 0, 0, 0.8);
    }
    
    /* Number text (1/3 etc) */
    .numbertext {
      color: #f2f2f2;
      font-size: 12px;
      padding: 8px 12px;
      position: absolute;
      top: 0;
    }
      
    img {
      margin-bottom: -4px;
      image-orientation: from-image;
    }
    
    .caption-container {
      text-align: center;
      background-color: black;
      padding: 2px 16px;
      color: white;
    }
    
    .demo {
      opacity: 0.6;
    }
    
    .active,
    .demo:hover {
      opacity: 1;
    }
    
    img.hover-shadow {
      transition: 0.3s
    }
    
    .hover-shadow:hover {
      box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2), 0 6px 20px 0 rgba(0, 0, 0, 0.19)
    }
  
  
  @media (max-width:800px) {
    .left, .main, .right {
      width:100%;/*The width is 100%, when the viewport is 800px or smaller*/
    }
    }
  
  
  .footer{
    background: #00795f;
    padding:20px 0;
    margin-top: 100px;
    text-align: center;
    clear: both;
    color: #ffff;
  }