h1 {text-decoration:underline;font-family:arial}
h2 {font-family:arial}
a {color: blue;text-style:bold}

table {width:50%;background-color:white;border: 1px solid black; cellspacing:1px;border-collapse:collapse} 
th {background-color:blue;color:white;font-size:20;font-family:arial;border: 2px solid black;padding:3px 7px 3px 7px}   
tr {background-color:lightblue;} 
td {font-size:18;font-family:arial;border: 2px solid black;padding:3px 7px 3px 7px } 
.left {text-align:left;}
.right {text-align:right;}
.center {text-align:center;}
.alt {background-color:#87ceeb}
tr.header {background-color:white;font-size:24;font-family:arial;border: 2px solid black;padding:3px 7px 3px 7px;font-weight: bold;} 
tr:hover {background-color:#00bfff}
tr.header {    cursor:pointer;}
#aufgabe {font-size:18;font-family:arial;border: 2px solid black;padding:3px 7px 3px 7px } 