nav {text-align: center;
    margin-bottom: 20px;
    border-bottom: 2px solid #eee;
    padding-bottom: 10px;
}
img {
    display: block;
    margin-left: auto;
    margin-right: auto;
}
.headings {
    text-align: center;
}

#about p {
    text-align: left;
}
table {
    text-align: center;
    width: 80%;
    margin: 20px auto;
    border-collapse: collapse;
}

th, td {
    border: 1px solid #ccc;
    padding: 8px;
}
footer {
    text-align: center;
    border-top: 2px solid #eee;
    margin-top: 40px;
    padding-top: 20px;
}