body
{
  font-family: Arial, sans-serif;
}

html
{
  box-sizing: border-box;
}

*, *:before, *:after
{
  box-sizing: inherit;
}

#mainDiv
{
  width: 50%;
  margin: 0 auto;
}

th, td
{
  border: 1px solid lightgrey;
}

thead
{
  background-color: rgba(0,0,0,.2);
}

tfoot td
{
  text-align: center !important;
}