body {
   background-image: url("yellow.jpg");
  
} 
<link rel="icon" type"image/jpg" href="favicon-16x16.png">

h1 {
  color: black;
  text-align: center;
 font-family: '';
  border-style: outset;
  border-width: 0.5em;
  border-color: black;
  border-radius: 0.5em;
  
   
	background-color: white;
}
ul.sticky {
	position: sticky;
  top: 0;
}
img
{  
  margin: 1em;
  width: 30em;
  height: 20em;
   border-style: outset;
  border-width: 0.5em;
  border-color: black;
  border-radius: 0.5em;
  transition: width 2s, height 2s;
  

}


.button {
  display: inline-block;
  padding: 10px 15px;
  font-size: 14.5px;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  outline: none;
  color: #fff;
  background-color: gray;
  border: none;
  border-radius: 10px;
  box-shadow: 0 7px #999;
}

.button:hover {background-color: lightgray}

.button:active {
  background-color: black;
  box-shadow: 0 5px #666;
  transform: translateY(4px);
  
}

p {
  color: black;
  text-align: center;
  font-family: Courier New, monospace;
  font-size: 1.5em;
  margin: 5em 5em 5em 5em;
}


	p:hover, h2:hover, a:hover, table:hover {
	background-color: white;  } 
		

	table, th, td {
  border:1px solid black;
}
	
img:hover{
	width: 40em;
	height: 30em;
}

.länk {
	font-size: 5em; 
}

ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333333;
}

ul li {
  float: left;
}

ul li a {
  display: block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
  font-family: Courier New, monospace;
  font-size: 1.5em;
}

ul li a:hover {
  background-color: #111111;
}

.dark-mode {
    
 
 background-image: url("purple.jpg");
}