h1 {
    color: red;
}
body {
    margin: 30px;
    font-family: Arial, Helvetica, sans-serif;
}
article {
    float:left;
    width: 70%;
}
aside {
    float: left;
    width: 20%;
    color:blue;
}
footer {
    clear: both;
}
p {
    margin:20px;
    display: block;
}
div {
    margin: 20px;
}
.ejemplo {
    font-family: Verdana, Geneva, Tahoma, sans-serif;
}
ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: row;
}
li {
    flex-grow: 1;
}
a {
    display: block;
    padding: 1em;
    background-color: lightcoral;
    text-align: center;
    margin-bottom: 0.2em;
    text-decoration: none;
    color: white;
}
a:hover {
    background-color: gray;
}
span {
    margin: 20px;
    padding: 20px;
}