Hi, does anyone know why my tooltip only opens up to the top? (It gets cut off when I scroll down).
Also, how do I make my header sticky? It does not seem to work.
Attached is my CSS code.

#tooltip
{
  text-align: center;
  color: #fff;
  background: #111;
  position: absolute;
  z-index: 100;
  padding: 15px;
  width: max-content; 
max-width: 200px;
}
 
  #tooltip:after /* triangle decoration */
  {
    width: 0;
    height: 0;
    border-left: 10px solid transparent;
    border-right: 10px solid transparent;
    border-top: 10px solid #111;
    content: '';
    position: absolute;
    left: 50%;
    bottom: -10px;
    margin-left: -10px;
  }
 
    #tooltip.top:after
    {
      border-top-color: transparent;
      border-bottom: 10px solid #111;
      top: -20px;
      bottom: auto;
    }
 
    #tooltip.left:after
    {
      left: 10px;
      margin: 0;
    }
 
    #tooltip.right:after
    {
      right: 10px;
      left: auto;
      margin: 0;
    }

table.my_table {
 font-size: 11px;
 border-collapse: collapse;
 border: solid 2px;
 width: 100%;
}

table.my_table td, table.my_table th {
 padding: 2px;
 text-align: center;
 margin: 0;
 border: solid 1px;
}

table.my_table th {
 background-color: #DCDCDC;
 border: solid 1px;
 border-bottom: solid 2px;
 position: -webkit-sticky;
 position: sticky;
 top: 0;
 z-index: 2;
}