margin: auto;

This can be due to:

font-size: 24px; a:hover { padding: 0;

Page not found (error 404)

color: #FECC04; font-weight: normal; http://site.altervista.org/Page.html is different from http://site.altervista.org/page.html .orange { body { text-decoration: none; Error 404 :( } Pay attetion to UPPER and LOWER cases
margin-top: 5%; list-style: disc;