body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: gray;
}

header {
    background-color: black;
    color: white;
    text-align: center;
    padding: 1em 0;
}

 ul {
    list-style-type: none;
    padding: 0;
}

 ul li {
    display: inline;
    margin: 0 15px;
}

 a {
    color: red;
    text-decoration: none;
}

main {
    padding: 20px;
}

section {
    margin-bottom: 30px;
    background-color: white;
    padding: 15px;
    border: 8px;
}

img {
aligen:"center";
    width: 200px
    height: 200px;
    border-radius: 4px;
<br>;
}

footer {
    background-color: black;
    color: white;
    text-align: center;
    padding: 10px 0;
    position: relative;
    width: 100%;
}