body {
    font-family:Arial, Helvetica, sans-serif;
}

header.topPage {
    display: flex;
}
header.topPage img {
    border:5px #000 solid;
}

header.topPage nav ul li,
footer nav ul li {
   display: inline-block;
   list-style-type: none;
}

header.topPage nav ul li a {
    text-decoration: none;
    color: #99f;
}

section article {
    background-color: #eee;
    margin: 10px;
}

section article:nth-child(2) h3 {
    color: #00f;
}

section article:nth-child(3) h3 {
    color: #f00;
}

section article h3 {
    padding: 10px;
    line-height: 0; 
}
section article p {
   padding: 10px;
}

section article h3::first-letter {
    text-transform: uppercase;
}


section article header,
section article footer {
    background-color: #ccc;
    padding: 10px;
}



section header:hover h1 {
    text-decoration: underline;
}



div[class^='box_'] {
    display:inline-block; 
    width:50px; 
    height:50px;
    background-color: #9f9;
    margin: 10px;
    padding: 10px;
}

div[class^='megaBox_'] {
    display:inline-block; 
    width:80px; 
    height:80px;
    background-color: #f99;
    margin: 10px;
    padding: 10px;
}

footer nav {
    text-align: center;
}
footer nav ul li a {
    text-decoration: none;
    color: #999;
}