main {
    max-width: 840px;
}
aside { 
    width:20rem;
    margin: 1rem;
    padding: 1rem;
    background-color: #f0f0f0;
    color: #333;
    text-align: center;
}
aside img {
    width: 200px;
    height: auto;
}
main img {
    width: 150px;
    height: auto;
}
p { 
    padding: 0;
}
footer { 
    margin-top: 15px;
    border-top: 1px solid #000;
    text-align: center;
}