CSS problemer.

border: 20px solid black;

Brug solid som parameter til din border.

Her er mit CSS

font {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px}
.overskrift_stor {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 24px; font-weight: normal; color: #FFFFFF}
.overskrift {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 14px; font-weight: bold; border-color: black black black #006666; border-style: none}
.menu {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; line-height: 50px; font-weight: bold; color: #FFFFFF; border-color: black black black #006666; border-style: solid; border-top-width: 0px; border-right-width: 0px; border-bottom-width: 0px; border-left-width: 0px}
.topmenu {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; font-weight: bold; color: #FFFFF; text-decoration: none}
td {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 12px; color: #000000}
.small {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 9px; font-style: italic; color: #666666}
.topmenu_markeret {  font-family: Verdana, Arial, Helvetica, sans-serif; font-size: 14px; color: #003333; font-weight: bold}

a {  color: #666666}

BODY{
  scrollbar-3d-light-color: #003300;
  scrollbar-arrow-color: #003300;
  scrollbar-base-color: #003300;
  scrollbar-dark-shadow-color: #003300;
  scrollbar-face-color: #FFFFFF;
  scrollbar-highlight-color: #FFFFFF;
  scrollbar-shadow-color: #FFFFFF;
}

body {

    background-color: white;
   
    }

  table.kalender {

    font: 12px verdana, sans-serif;
}

  td.style1 {
 
      background-color: #CCCCCC;
}
 
  td.style2 {
 
      background-color: #DDDDDD;
}
 
  th.kalender {

    text-align: left;
}

.vejledning {

    font: 12px verdana, sans-serif;
}     


  div.logo {
     
      float:left;
    width: 50px;
}

  .overskrift1 {
 
      font: bold 18px verdana, sans-serif;
}

  .overskrift2 {
 
      font: 16px verdana, sans-serif;
}

.gruppenavn {

    font: 50px verdana, sans-serif; font-style: italic;
}


a.menu:link {
    color: white;
    font: 12px verdana, sans-serif;
    text-decoration:none;

}


a.menu:visited {
    color: white;
    font: 12px verdana, sans-serif;
    text-decoration:none;

}

a.menu:active {
    font: 12px verdana, sans-serif;
    text-decoration:none;

}
a.menu:hover {
    color:yellow;
    font: 12px verdana, sans-serif;
      text-decoration:none;

}

Border="0">...! er det det du mener...!

Fik du tjek på det?