hr {
margin: 10px;
}
h1 {
text-align: center;
}
.nav-ul {
list-style-type: none;
}
.nav-li {
padding: 10px; margin: 10px; display: inline;
}
.content {
margin: 30px;
}
@media only screen and (max-width: 800px) {
/* For tablets: */ .content { margin: 20px; }
}
@media only screen and (max-width: 500px) {
/* For mobile phones: */ .content { margin: 10px; }
}