BODY {
   background-color: beige;
}
 
#headerBoxStyle {
  background: magenta;
  font-size:   22px;
  font-weight: bolder; 
  color:       brown;
  text-align:  center;
}
 
#treeBoxStyle {
  background: red;
}
 
#fileBoxStyle {
  background: blue;
}

.fileItemStyle {
  font-size:   18px;
  font-weight: bolder; 
  color:       green;
}