table {table-layout: fixed;}
#tab3 table {
border: solid black 1px;
background: #FFFFFF;
width: 30em;
border-collapse: collapse;
}

#tab3 th {
text-align: left;
}
#tab3 tr.zahlavi th {
border-bottom: solid black 2px;
}
#tab3 tr {
background: #FFFFFF;
}
#tab3 th,
#tab3 td {
height: 3ex;
border: solid black 1px;
 font-family: georgia, times, serif; font-size: 12px;
}
#tab3 tr.sudy * {
background: #FFFFFF;
}
#tab3 tr.zahlavi th {
background: #FFFFFF;
}