a {
        text-decoration: none;
}

a:hover {
        border-top-style: solid;
        border-top-width: thin;
        border-bottom-style: solid;
        border-bottom-width: thin;
}

body {
        background-image: url("background.jpg");
}

div.centro {
        text-align: center;
}

div.introducao {
        font-size: bigger;
        text-align: center;
}

div.rodape {
        position: absolute;
        top: 90%;
        width: 100%;
        font-size: smaller;
}

a img {
        border-style: none;
}