body{background-position-x: center; background-position-y: top; width: 75%; margin: auto;}
h1,h2{color: #ffcc00; padding: 10px; background-repeat: repeat-x;}
h1{text-align: center; background-image: url(img/madera.jpg);}
ul{font-family: 'Courier New', Courier, monospace; padding-left: 100px;}
.ico1{content: url(img/valid-html401.png);}
.ico2{content: url(img/vcss.gif);}
.ico3{content: url(img/valid-xhtml11.png);}
ul.lista1{list-style-type: square;}
ul.lista2{list-style-image: url(img/YES01B.ICO);}