p { }
a:link { font-size: 12px; font-family: Verdana, Arial, Helvetica, sans-serif; text-decoration: none; margin-right: 10px; margin-left: 10px; }
a:visited { color: black; text-decoration: none; }
a:hover { color: white; background-color: black; }
a:active { }
.sprechzeiten { background-image: url(../bilder/sprechzeiten.jpg); background-repeat: no-repeat; text-align: center; /* ebenfalls für den IE nötig */
margin-left: auto; margin-right: auto; position: relative; /*ohne gehts nicht*/
top: 25%; width: 620px; height: 420px; /*Nur als Beispiel*/
}
.aktiv { color: black; background-color: #ccc; }

body { font-size: 11px; font-family: Verdana, Arial, Helvetica, sans-serif; word-wrap: break-word; padding: 0; margin: 0; overflow: hidden; } 

#main { background: url(../bilder/hauptlayer.jpg) no-repeat center;  padding: 7px;  margin: -300px 0 0 -400px; position:absolute; top: 50%; left: 50%; width: 800px; height: 600px;  }