* { box-sizing: border-box;}
body {
  
  
    font-family: Arial, Helvetica, sans-serif;
}


#wrapper {
  
  
    width: 80%;
    margin-left: auto;
    margin-right: auto;
    border: thin solid black;
}


header {
  
    margin: 10px;
    padding: 10px;
    background-color: grey;
    color: white;
}



header > img {
  
  
  
    width: 20%;
    height: auto;
    float: right;
}

.clearright {
  
  
    clear: right;
}
nav {
    display: flex;
    justify-content: center;
    text-align: center;
    flex: 1;
}


nav > div {
  
  
  
    background-color: #f1f1f1;
    margin: 10px;
    padding: 10px;
    font-size: 20px;


}


nav > div > a {
  
  
    color: steelblue;
    font-weight: bold;
    text-decoration: none;
  
  
}
nav > div > a:hover {
  
  
    color: red;
  
  
    text-decoration: underline;
}
main {
  
  
    display: flex;
  
  
}
main > div {
  
  
  
    background-color: #f1f1f1;
    margin: 10px;
    padding: 10px;
  
  
}

.left {
  
  
    flex: 2;
  
  
}
.left > img {
  
  
    width: 40%;
    height: auto;
    float: right;
    margin: 10px;
}


.right {
  
  
    flex: 1;
}
footer {
  
  
    background-color: gainsboro;
    margin: 10px;
    padding: 10px;
  
  
}
footer p {
  
    text-align: center;
}

@media only screen and (max-width: 1024px) {
  
    #wrapper {
        width: 100%;
        border: none;
      
      
    }
    header > img {
        width: 25%;
        height: auto;
        float: right;
      
      
    }
}
@media only screen and (max-width: 510px) {
  
  

    nav {
      
        flex-direction: column;
    }   
  
    main {
      
        flex-direction: column;
      
    }   
  
    nav > div {
      
        width: auto;
        margin: 5px;
      
      
    }
    main > div {
      
      
        margin: 5px;
      
      
    }
  
    header > img {
        width: 40%;
        height: auto;
        float: right;
      
    }
    .left > img {
        width: 100%;
        height: auto;
        float: none;
        margin: 0;
      
      
    }
}