body {
    background-color: lightgray;
    }
    h1, h2 {
    text-shadow: 3px 2px lightgray;
    text-align: center;
    }

    #Logo {
    display: block;
    margin-left: auto;
    margin-right: auto;
    }

    #sample1 {
        display: block;
        width: 860px;
        height: 500px;
        background-color: lightgrey;
        margin-left: auto;
        margin-right: auto;
    }

    #sample2 {
        display: none;
        width: 860px;
        height: 600px;
        background-color: lightgrey;
        margin-left: auto;
        margin-right: auto;
    }

    #sample3 {
        display: none;
        width: 860px;
        height: 600px;
        background-color: #2b2b2b;
        margin-left: auto;
        margin-right: auto;
    }

    #sample4 {
        display: none;
        width: 860px;
        height: 600px;
        margin-left: auto;
        margin-right: auto;

    }
    /*
    code {
        background-color: lightblue;
    }
    */
    nav {
        font-size: 30px;
        margin: auto;
        width: 40%;
    }

    #buttons {
        background-color: rgba(0, 176, 206, 0.6);
        display: block;
        margin-left: auto;
        margin-right: auto;
        padding: 10px;
        width: 40%;
    }

    .ln { color: #606366; font-weight: normal; font-style: normal; }
    .s0 { color: rgb(204,120,50); }
    .s1 { color: rgb(169,183,198); }
    .s2 { color: rgb(128,128,128); }
    .s3 { color: rgb(106,135,89); }
    .s4 { color: rgb(104,151,187); }

/* menu bar */
    ul {
    font-size: 20px;
  list-style-type: none;
  margin: auto;
  width: 50%;
  padding: 0;
  overflow: hidden;
  background-color: #333;
}

li {
  float: left;
}

li a, .dropbtn {
  display: inline-block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

li a:hover, .dropdown:hover .dropbtn {
  background-color: #4286f4;
}

li.dropdown {
  display: inline-block;
}

.dropdown-content {
  display: none;
  position: absolute;
  background-color: #f9f9f9;
  min-width: 160px;
  box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
  z-index: 1;
}

.dropdown-content a {
  color: black;
  padding: 12px 16px;
  text-decoration: none;
  display: block;
  text-align: left;
}

.dropdown-content a:hover {background-color: #f1f1f1}

.dropdown:hover .dropdown-content {
  display: block;
}