*       { line-height: 1em; }
td, div { vertical-align: top; }
html    { height: 100%; font-family:'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif; }
h1      { font-size: 2em; text-align: center; margin-bottom: 3em; letter-spacing: 1em; }
nav     { width: 80%; margin: auto; }
ul      { display: flex; flex-direction: row; justify-content: space-around;}    
nav>ul>li   { list-style: none; width: 20%; text-align: center; font-size: 1.5em; }