#banner{
    background-color: maroon;
    padding: 10px;
    weidth: 100%;
    color: white;
    font-size: x-large;
    text-align: center;
}

#navigation{
    background-color: aqua;
    height : 1000px;
    width: 15%;
    padding: 10px;
    float: left;
}
#introduction{
    background-color: gainsboro;
    text-align: justify;
    padding: 5px;
    padding-left: 17%;
    padding-right: 5%;
    border-radius: 15px;
}

footer{
    background-color: maroon;
    padding: 3px;
    width: 100%;
    text-align: center;
}

.tab {
  overflow: hidden;
  border: 1px solid #ccc;
  background-color: #f1f1f1;
}

/* Style the buttons that are used to open the tab content */
.tab button {
  background-color: inherit;
  float: left;
  border: none;
  outline: none;
  cursor: pointer;
  padding: 14px 16px;
  transition: 0.3s;
}

/* Change background color of buttons on hover */
.tab button:hover {
  background-color: #ddd;
}

/* Create an active/current tablink class */
.tab button.active {
  background-color: #ccc;
}

/* Style the tab content */
.tabcontent {
  display: none;
  padding: 6px 12px;
  border: 1px solid #ccc;
  border-top: none;
}
.book button{
	width:150;
	height:250;
	color:rad;
}
li button{
    width: 300px;
}