h1,h2 {

background-color: blue;
color: yellow

}

body {

background-color: green;
color: yellow

}

.imagec {
display: block;
margin-left: auto
margin-right: auto
padding: 20px;
background-color: silver;
border-color: brown;
border-width: 10px;
border-style: solid;
border-bottom-left-radius: 50%;
border-bottom-right-radius: 50%;
border-top-left-radius: 50%;
border-top-right-radius: 50%;
}


.div1 {
width: 50%;
height:50%;
float: left;
}


.div2 {
width: 50%;
height:50%;
float: right;
}

.div3 {
width: 100%;
height:20%;
}

div .books {
  box-sizing: content-box;  
  width: 300px;
  height: 400px;
  padding: 30px;  
  border: 10px solid blue;
  overflow: scroll;
}
.lib {
   table-layout: auto;
   overflow:scroll
   height: 300px;
   border: 1px solid black;
}


.buttonback {
  background-color: black;
  border: none;
  color: white;
  padding: 15px 32px;
  text-align: center;
  text-decoration: none;
  font-size: 24px;
  display: inline-block;
  font-size: 16px;
  cursor: pointer;
  border-radius: 15px;
  box-shadow: 0 9px #999;
 
}
/* Popup container */
.popup {
  position: relative;
  display: inline-block;
  cursor: pointer;
}

/* The actual popup (appears on top) */
.popup .popuptext {
  visibility: hidden;
  width: 160px;
  background-color: #555;
  color: #fff;
  text-align: center;
  border-radius: 6px;
  padding: 8px 0;
  position: absolute;
  z-index: 1;
  bottom: 125%;
  left: 50%;
  margin-left: -80px;
}

/* Popup arrow */
.popup .popuptext::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  margin-left: -5px;
  border-width: 5px;
  border-style: solid;
  border-color: #555 transparent transparent transparent;
}

/* Toggle this class when clicking on the popup container (hide and show the popup) */
.popup .show {
  visibility: visible;
  -webkit-animation: fadeIn 1s;
  animation: fadeIn 1s
}

/* Add animation (fade in the popup) */
@-webkit-keyframes fadeIn {
  from {opacity: 0;}
  to {opacity: 1;}
}

@keyframes fadeIn {
  from {opacity: 0;}
  to {opacity:1 ;}
}
#myBtn {
  display: none; /* Hidden by default */
  position: fixed; /* Fixed/sticky position */
  bottom: 20px; /* Place the button at the bottom of the page */
  right: 30px; /* Place the button 30px from the right */
  z-index: 99; /* Make sure it does not overlap */
  border: none; /* Remove borders */
  outline: none; /* Remove outline */
  background-color: red; /* Set a background color */
  color: white; /* Text color */
  cursor: pointer; /* Add a mouse pointer on hover */
  padding: 15px; /* Some padding */
  border-radius: 10px; /* Rounded corners */
  font-size: 18px; /* Increase font size */
}

#myBtn:hover {
  background-color: #555; /* Add a dark-grey background on hover */
}

p.small {
  line-height: 0.7;
}

p.big {
  line-height: 1.8;
}
/* Create two columns/boxes that floats next to each other */
nav {
  float: left;
  width:30%;
  padding: 20px;
  height: 100%;
}

/* Style the list inside the menu */
nav_ul {
  list-style-type: none;
  padding: 0;
}

article {
  float: right;
  padding: 20px;
  width: 60%;
  color: orange; 
}

/* Clear floats after the columns */
section:after {
  content: "";
  display: table;
  clear: both;
}


/* Responsive layout - makes the two columns/boxes stack on top of each other instead of next to each other, on small screens */
@media (max-width: 600px) {
  nav, article {
    width: 100%;
    height: auto;
  }
}
/* Extra style for the cancel button (red) */
.cancelbtn {
  width: auto;
  height: auto;
  padding: 10px 18px;
  background-color: red;
}